Calling kvm_mmu_slot_remove_write_access() for a deleted slot does
nothing but search for non-existent mmu pages which have mappings to
that deleted memory; this is safe but a waste of time.
Since we want to make the function rmap based in a later patch, in a
manner which makes it unsafe to be called for a deleted slot, we makes
the caller see if the slot is non-zero and being dirty logged.
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
We have two issues in current code:
- if target gfn is used as its page table, guest will refault then kvm will use
small page size to map it. We need two #PF to fix its shadow page table
- sometimes, say a exception is triggered during vm-exit caused by #PF
(see handle_exception() in vmx.c), we remove all the shadow pages shadowed
by the target gfn before go into page fault path, it will cause infinite
loop:
delete shadow pages shadowed by the gfn -> try to use large page size to map
the gfn -> retry the access ->...
To fix these, we can adjust page size early if the target gfn is used as page
table
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
If the write-fault access is from supervisor and CR0.WP is not set on the
vcpu, kvm will fix it by adjusting pte access - it sets the W bit on pte
and clears U bit. This is the chance that kvm can change pte access from
readonly to writable
Unfortunately, the pte access is the access of 'direct' shadow page table,
means direct sp.role.access = pte_access, then we will create a writable
spte entry on the readonly shadow page table. It will cause Dirty bit is
not tracked when two guest ptes point to the same large page. Note, it
does not have other impact except Dirty bit since cr0.wp is encoded into
sp.role
It can be fixed by adjusting pte access before establishing shadow page
table. Also, after that, no mmu specified code exists in the common function
and drop two parameters in set_spte
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Opcodes:
TEST
CMP
ADD
ADC
SUB
SBB
XOR
OR
AND
Acked-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi.kivity@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
We emulate arithmetic opcodes by executing a "similar" (same operation,
different operands) on the cpu. This ensures accurate emulation, esp. wrt.
eflags. However, the prologue and epilogue around the opcode is fairly long,
consisting of a switch (for the operand size) and code to load and save the
operands. This is repeated for every opcode.
This patch introduces an alternative way to emulate arithmetic opcodes.
Instead of the above, we have four (three on i386) functions consisting
of just the opcode and a ret; one for each operand size. For example:
.align 8
em_notb:
not %al
ret
.align 8
em_notw:
not %ax
ret
.align 8
em_notl:
not %eax
ret
.align 8
em_notq:
not %rax
ret
The prologue and epilogue are shared across all opcodes. Note the functions
use a special calling convention; notably eflags is an input/output parameter
and is not clobbered. Rather than dispatching the four functions through a
jump table, the functions are declared as a constant size (8) so their address
can be calculated.
Acked-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi.kivity@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
CPL is always 0 when in real mode, and always 3 when virtual 8086 mode.
Using values other than those can cause failures on operations that
check CPL.
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Use dynamic percpu allocations for the shared msrs structure,
to avoid using the limited reserved percpu space.
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
MMU code tries to avoid if()s HW is not able to predict reliably by using
bitwise operation to streamline code execution, but in case of a dirty bit
folding this gives us nothing since write_fault is checked right before
the folding code. Lets just piggyback onto the if() to make code more clear.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
With emulate_invalid_guest_state=0 if a vcpu is in real mode VMX can
enter the vcpu with smaller segment limit than guest configured. If the
guest tries to access pass this limit it will get #GP at which point
instruction will be emulated with correct segment limit applied. If
during the emulation IO is detected it is not handled correctly. Vcpu
thread should exit to userspace to serve the IO, but it returns to the
guest instead. Since emulation is not completed till userspace completes
the IO the faulty instruction is re-executed ad infinitum.
The patch fixes that by exiting to userspace if IO happens during
instruction emulation.
Reported-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Segment registers will be fixed according to current emulation policy
during switching to real mode for the first time.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Currently when emulation of invalid guest state is enable
(emulate_invalid_guest_state=1) segment registers are still fixed for
entry to vm86 mode some times. Segment register fixing is avoided in
enter_rmode(), but vmx_set_segment() still does it unconditionally.
The patch fixes it.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Currently it allows entering vm86 mode if segment limit is greater than
0xffff and db bit is set. Both of those can cause incorrect execution of
instruction by cpu since in vm86 mode limit will be set to 0xffff and db
will be forced to 0.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
According to Intel SDM Vol3 Section 5.5 "Privilege Levels" and 5.6
"Privilege Level Checking When Accessing Data Segments" RPL checking is
done during loading of a segment selector, not during data access. We
already do checking during segment selector loading, so drop the check
during data access. Checking RPL during data access triggers #GP if
after transition from real mode to protected mode RPL bits in a segment
selector are set.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Segment descriptor's base is fixed by call to fix_rmode_seg(). Not need
to do it twice.
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
The code for SS and CS does the same thing fix_rmode_seg() is doing.
Use it instead of hand crafted code.
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
VMX without unrestricted mode cannot virtualize real mode, so if
emulate_invalid_guest_state=0 kvm uses vm86 mode to approximate
it. Sometimes, when guest moves from protected mode to real mode, it
leaves segment descriptors in a state not suitable for use by vm86 mode
virtualization, so we keep shadow copy of segment descriptors for internal
use and load fake register to VMCS for guest entry to succeed. Till
now we kept shadow for all segments except SS and CS (for SS and CS we
returned parameters directly from VMCS), but since commit a5625189f6
emulator enforces segment limits in real mode. This causes #GP during move
from protected mode to real mode when emulator fetches first instruction
after moving to real mode since it uses incorrect CS base and limit to
linearize the %rip. Fix by keeping shadow for SS and CS too.
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
rmode_segment_valid() checks if segment descriptor can be used to enter
vm86 mode. VMX spec mandates that in vm86 mode CS register will be of
type data, not code. Lets allow guest entry with vm86 mode if the only
problem with CS register is incorrect type. Otherwise entire real mode
will be emulated.
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Set segment fields explicitly instead of using binary operations.
No behaviour changes.
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
The kvm i8254 emulation for counter 0 (but not for counters 1 and 2)
has at least two bugs in mode 0:
1. The OUT bit, computed by pit_get_out(), is never set high.
2. The counter value, computed by pit_get_count(), wraps back around to
the initial counter value, rather than wrapping back to 0xFFFF
(which is the behavior described in the comment in __kpit_elapsed,
the behavior implemented by qemu, and the behavior observed on AMD
hardware).
The bug stems from __kpit_elapsed computing the elapsed time mod the
initial counter value (stored as nanoseconds in ps->period). This is both
unnecessary (none of the callers of kpit_elapsed expect the value to be
at most the initial counter value) and incorrect (it causes pit_get_count
to appear to wrap around to the initial counter value rather than 0xFFFF).
Removing this mod from __kpit_elapsed fixes both of the above bugs.
Signed-off-by: Nickolai Zeldovich <nickolai@csail.mit.edu>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
There's no need for this to be an int, it holds a boolean.
Move to the end of the struct for alignment.
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
It's easy to confuse KVM_MEMORY_SLOTS and KVM_MEM_SLOTS_NUM. One is
the user accessible slots and the other is user + private. Make this
more obvious.
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
According to Intel SDM Volume 3 Section 10.8.1 "Interrupt Handling with
the Pentium 4 and Intel Xeon Processors" and Section 10.8.2 "Interrupt
Handling with the P6 Family and Pentium Processors" ExtINT interrupts are
sent directly to the processor core for handling. Currently KVM checks
APIC before it considers ExtINT interrupts for injection which is
backwards from the spec. Make code behave according to the SDM.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Acked-by: "Zhang, Yang Z" <yang.z.zhang@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
MOV immediate instruction (opcodes 0xB8-0xBF) may take 64-bit operand.
The previous emulation implementation assumes the operand is no longer than 32.
Adding OpImm64 for this matter.
Fixes https://bugzilla.redhat.com/show_bug.cgi?id=881579
Signed-off-by: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Pull KVM updates from Marcelo Tosatti:
"Considerable KVM/PPC work, x86 kvmclock vsyscall support,
IA32_TSC_ADJUST MSR emulation, amongst others."
Fix up trivial conflict in kernel/sched/core.c due to cross-cpu
migration notifier added next to rq migration call-back.
* tag 'kvm-3.8-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (156 commits)
KVM: emulator: fix real mode segment checks in address linearization
VMX: remove unneeded enable_unrestricted_guest check
KVM: VMX: fix DPL during entry to protected mode
x86/kexec: crash_vmclear_local_vmcss needs __rcu
kvm: Fix irqfd resampler list walk
KVM: VMX: provide the vmclear function and a bitmap to support VMCLEAR in kdump
x86/kexec: VMCLEAR VMCSs loaded on all cpus if necessary
KVM: MMU: optimize for set_spte
KVM: PPC: booke: Get/set guest EPCR register using ONE_REG interface
KVM: PPC: bookehv: Add EPCR support in mtspr/mfspr emulation
KVM: PPC: bookehv: Add guest computation mode for irq delivery
KVM: PPC: Make EPCR a valid field for booke64 and bookehv
KVM: PPC: booke: Extend MAS2 EPN mask for 64-bit
KVM: PPC: e500: Mask MAS2 EPN high 32-bits in 32/64 tlbwe emulation
KVM: PPC: Mask ea's high 32-bits in 32/64 instr emulation
KVM: PPC: e500: Add emulation helper for getting instruction ea
KVM: PPC: bookehv64: Add support for interrupt handling
KVM: PPC: bookehv: Remove GET_VCPU macro from exception handler
KVM: PPC: booke: Fix get_tb() compile error on 64-bit
KVM: PPC: e500: Silence bogus GCC warning in tlb code
...
In real mode CS register is writable, so do not #GP on write.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
If enable_unrestricted_guest is true vmx->rmode.vm86_active will
always be false.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
On CPUs without support for unrestricted guests DPL cannot be smaller
than RPL for data segments during guest entry, but this state can occurs
if a data segment selector changes while vcpu is in real mode to a value
with lowest two bits != 00. Fix that by forcing DPL == RPL on transition
to protected mode.
This is a regression introduced by c865c43de6.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
The vmclear function will be assigned to the callback function pointer
when loading kvm-intel module. And the bitmap indicates whether we
should do VMCLEAR operation in kdump. The bits in the bitmap are
set/unset according to different conditions.
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
There are two cases we need to adjust page size in set_spte:
1): the one is other vcpu creates new sp in the window between mapping_level()
and acquiring mmu-lock.
2): the another case is the new sp is created by itself (page-fault path) when
guest uses the target gfn as its page table.
In current code, set_spte drop the spte and emulate the access for these case,
it works not good:
- for the case 1, it may destroy the mapping established by other vcpu, and
do expensive instruction emulation.
- for the case 2, it may emulate the access even if the guest is accessing
the page which not used as page table. There is a example, 0~2M is used as
huge page in guest, in this huge page, only page 3 used as page table, then
guest read/writes on other pages can cause instruction emulation.
Both of these cases can be fixed by allowing guest to retry the access, it
will refault, then we can establish the mapping by using small page
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
VMX behaves now as SVM wrt to FPU initialization. Code has been moved to
generic code path. General-purpose registers are now cleared on reset and
INIT. SVM code properly initializes EDX.
Signed-off-by: Julian Stecklina <jsteckli@os.inf.tu-dresden.de>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Bit24 in VMX_EPT_VPID_CAP_MASI is not used for address-specific invalidation capability
reporting, so remove it from KVM to avoid conflicts in future.
Signed-off-by: Zhang Xiantao <xiantao.zhang@intel.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Bit 6 in EPT vmexit's exit qualification is not defined in SDM, so remove it.
Signed-off-by: Zhang Xiantao <xiantao.zhang@intel.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
CPUID.7.0.EBX[1]=1 indicates IA32_TSC_ADJUST MSR 0x3b is supported
Basic design is to emulate the MSR by allowing reads and writes to a guest
vcpu specific location to store the value of the emulated MSR while adding
the value to the vmcs tsc_offset. In this way the IA32_TSC_ADJUST value will
be included in all reads to the TSC MSR whether through rdmsr or rdtsc. This
is of course as long as the "use TSC counter offsetting" VM-execution control
is enabled as well as the IA32_TSC_ADJUST control.
However, because hardware will only return the TSC + IA32_TSC_ADJUST +
vmsc tsc_offset for a guest process when it does and rdtsc (with the correct
settings) the value of our virtualized IA32_TSC_ADJUST must be stored in one
of these three locations. The argument against storing it in the actual MSR
is performance. This is likely to be seldom used while the save/restore is
required on every transition. IA32_TSC_ADJUST was created as a way to solve
some issues with writing TSC itself so that is not an option either.
The remaining option, defined above as our solution has the problem of
returning incorrect vmcs tsc_offset values (unless we intercept and fix, not
done here) as mentioned above. However, more problematic is that storing the
data in vmcs tsc_offset will have a different semantic effect on the system
than does using the actual MSR. This is illustrated in the following example:
The hypervisor set the IA32_TSC_ADJUST, then the guest sets it and a guest
process performs a rdtsc. In this case the guest process will get
TSC + IA32_TSC_ADJUST_hyperviser + vmsc tsc_offset including
IA32_TSC_ADJUST_guest. While the total system semantics changed the semantics
as seen by the guest do not and hence this will not cause a problem.
Signed-off-by: Will Auld <will.auld@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
In order to track who initiated the call (host or guest) to modify an msr
value I have changed function call parameters along the call path. The
specific change is to add a struct pointer parameter that points to (index,
data, caller) information rather than having this information passed as
individual parameters.
The initial use for this capability is for updating the IA32_TSC_ADJUST msr
while setting the tsc value. It is anticipated that this capability is
useful for other tasks.
Signed-off-by: Will Auld <will.auld@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
vmcs->cpu indicates whether it exists on the target cpu, -1 means the vmcs
does not exist on any vcpu
If vcpu load vmcs with vmcs.cpu = -1, it can be directly added to cpu's percpu
list. The list can be corrupted if the cpu prefetch the vmcs's list before
reading vmcs->cpu. Meanwhile, we should remove vmcs from the list before
making vmcs->vcpu == -1 be visible
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
In loaded_vmcs_clear, loaded_vmcs->cpu is the fist parameter passed to
smp_call_function_single, if the target cpu is downing (doing cpu hot remove),
loaded_vmcs->cpu can become -1 then -1 is passed to smp_call_function_single
It can be triggered when vcpu is being destroyed, loaded_vmcs_clear is called
in the preemptionable context
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
As requested by Glauber, do not update kvmclock area on vcpu->pcpu
migration, in case the host has stable TSC.
This is to reduce cacheline bouncing.
Acked-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
With master clock, a pvclock clock read calculates:
ret = system_timestamp + [ (rdtsc + tsc_offset) - tsc_timestamp ]
Where 'rdtsc' is the host TSC.
system_timestamp and tsc_timestamp are unique, one tuple
per VM: the "master clock".
Given a host with synchronized TSCs, its obvious that
guest TSC must be matched for the above to guarantee monotonicity.
Allow master clock usage only if guest TSCs are synchronized.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
KVM added a global variable to guarantee monotonicity in the guest.
One of the reasons for that is that the time between
1. ktime_get_ts(×pec);
2. rdtscll(tsc);
Is variable. That is, given a host with stable TSC, suppose that
two VCPUs read the same time via ktime_get_ts() above.
The time required to execute 2. is not the same on those two instances
executing in different VCPUS (cache misses, interrupts...).
If the TSC value that is used by the host to interpolate when
calculating the monotonic time is the same value used to calculate
the tsc_timestamp value stored in the pvclock data structure, and
a single <system_timestamp, tsc_timestamp> tuple is visible to all
vcpus simultaneously, this problem disappears. See comment on top
of pvclock_update_vm_gtod_copy for details.
Monotonicity is then guaranteed by synchronicity of the host TSCs
and guest TSCs.
Set TSC stable pvclock flag in that case, allowing the guest to read
clock from userspace.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Register a notifier for clocksource change event. In case
the host switches to clock other than TSC, disable master
clock usage.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Otherwise its possible for an unrelated KVM_REQ_UPDATE_CLOCK (such as due to CPU
migration) to clear the bit.
Noticed by Paolo Bonzini.
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
In __emulate_1op_rax_rdx, we use "+a" and "+d" which are input/output
constraints, and *then* use "a" and "d" as input constraints. This is
incorrect, but happens to work on some versions of gcc.
However, it breaks gcc with -O0 and icc, and may break on future
versions of gcc.
Reported-and-tested-by: Melanie Blower <melanie.blower@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/B3584E72CFEBED439A3ECA9BCE67A4EF1B17AF90@FMSMSX107.amr.corp.intel.com
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
No need to check return value before breaking switch.
Signed-off-by: Guo Chao <yan@linux.vnet.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Return value of this function will be that of ioctl().
#include <stdio.h>
#include <linux/kvm.h>
int main () {
int fd;
fd = open ("/dev/kvm", 0);
fd = ioctl (fd, KVM_CREATE_VM, 0);
ioctl (fd, KVM_SET_TSS_ADDR, 0xfffff000);
perror ("");
return 0;
}
Output is "Operation not permitted". That's not what
we want.
Return -EINVAL in this case.
Signed-off-by: Guo Chao <yan@linux.vnet.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
We should avoid kfree()ing error pointer in kvm_vcpu_ioctl() and
kvm_arch_vcpu_ioctl().
Signed-off-by: Guo Chao <yan@linux.vnet.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
On hosts without the XSAVE support unprivileged local user can trigger
oops similar to the one below by setting X86_CR4_OSXSAVE bit in guest
cr4 register using KVM_SET_SREGS ioctl and later issuing KVM_RUN
ioctl.
invalid opcode: 0000 [#2] SMP
Modules linked in: tun ip6table_filter ip6_tables ebtable_nat ebtables
...
Pid: 24935, comm: zoog_kvm_monito Tainted: G D 3.2.0-3-686-pae
EIP: 0060:[<f8b9550c>] EFLAGS: 00210246 CPU: 0
EIP is at kvm_arch_vcpu_ioctl_run+0x92a/0xd13 [kvm]
EAX: 00000001 EBX: 000f387e ECX: 00000000 EDX: 00000000
ESI: 00000000 EDI: 00000000 EBP: ef5a0060 ESP: d7c63e70
DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
Process zoog_kvm_monito (pid: 24935, ti=d7c62000 task=ed84a0c0
task.ti=d7c62000)
Stack:
00000001 f70a1200 f8b940a9 ef5a0060 00000000 00200202 f8769009 00000000
ef5a0060 000f387e eda5c020 8722f9c8 00015bae 00000000 ed84a0c0 ed84a0c0
c12bf02d 0000ae80 ef7f8740 fffffffb f359b740 ef5a0060 f8b85dc1 0000ae80
Call Trace:
[<f8b940a9>] ? kvm_arch_vcpu_ioctl_set_sregs+0x2fe/0x308 [kvm]
...
[<c12bfb44>] ? syscall_call+0x7/0xb
Code: 89 e8 e8 14 ee ff ff ba 00 00 04 00 89 e8 e8 98 48 ff ff 85 c0 74
1e 83 7d 48 00 75 18 8b 85 08 07 00 00 31 c9 8b 95 0c 07 00 00 <0f> 01
d1 c7 45 48 01 00 00 00 c7 45 1c 01 00 00 00 0f ae f0 89
EIP: [<f8b9550c>] kvm_arch_vcpu_ioctl_run+0x92a/0xd13 [kvm] SS:ESP
0068:d7c63e70
QEMU first retrieves the supported features via KVM_GET_SUPPORTED_CPUID
and then sets them later. So guest's X86_FEATURE_XSAVE should be masked
out on hosts without X86_FEATURE_XSAVE, making kvm_set_cr4 with
X86_CR4_OSXSAVE fail. Userspaces that allow specifying guest cpuid with
X86_FEATURE_XSAVE even on hosts that do not support it, might be
susceptible to this attack from inside the guest as well.
Allow setting X86_CR4_OSXSAVE bit only if host has XSAVE support.
Signed-off-by: Petr Matousek <pmatouse@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
After commit b3356bf0db (KVM: emulator: optimize "rep ins" handling),
the pieces of io data can be collected and write them to the guest memory
or MMIO together
Unfortunately, kvm splits the mmio access into 8 bytes and store them to
vcpu->mmio_fragments. If the guest uses "rep ins" to move large data, it
will cause vcpu->mmio_fragments overflow
The bug can be exposed by isapc (-M isapc):
[23154.818733] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC
[ ......]
[23154.858083] Call Trace:
[23154.859874] [<ffffffffa04f0e17>] kvm_get_cr8+0x1d/0x28 [kvm]
[23154.861677] [<ffffffffa04fa6d4>] kvm_arch_vcpu_ioctl_run+0xcda/0xe45 [kvm]
[23154.863604] [<ffffffffa04f5a1a>] ? kvm_arch_vcpu_load+0x17b/0x180 [kvm]
Actually, we can use one mmio_fragment to store a large mmio access then
split it when we pass the mmio-exit-info to userspace. After that, we only
need two entries to store mmio info for the cross-mmio pages access
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This patch filters noslot pfn out from error pfns based on Marcelo comment:
noslot pfn is not a error pfn
After this patch,
- is_noslot_pfn indicates that the gfn is not in slot
- is_error_pfn indicates that the gfn is in slot but the error is occurred
when translate the gfn to pfn
- is_error_noslot_pfn indicates that the pfn either it is error pfns or it
is noslot pfn
And is_invalid_pfn can be removed, it makes the code more clean
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Merge reason: development work has dependency on kvm patches merged
upstream.
Conflicts:
arch/powerpc/include/asm/Kbuild
arch/powerpc/include/asm/kvm_para.h
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
The mmu_notifier_retry is not specific to any vcpu (and never will be)
so only take struct kvm as a parameter.
The motivation is the ARM mmu code that needs to call this from
somewhere where we long let go of the vcpu pointer.
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
We can not directly call kvm_release_pfn_clean to release the pfn
since we can meet noslot pfn which is used to cache mmio info into
spte
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Avi Kivity <avi@redhat.com>
Use __func__ instead of the function name in svm_hardware_enable since
those things tend to get out of sync. This also slims down printk line
length in conjunction with using pr_err.
No functionality change.
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Avi Kivity <avi@redhat.com>
Signed-off-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
The #PF with PFEC.RSV = 1 indicates that the guest is accessing MMIO, we
can not fix it if it is caused by delivery event. Reporting internal error
for this case
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
VM exits during Event Delivery is really unexpected if it is not caused
by Exceptions/EPT-VIOLATION/TASK_SWITCH, we'd better to report an internal
and freeze the guest, the VMM has the chance to check the guest
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
The only difference between FNAME(update_pte) and FNAME(pte_prefetch)
is that the former is allowed to prefetch gfn from dirty logged slot,
so introduce a common function to prefetch spte
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
The function does not depend on guest mmu mode, move it out from
paging_tmpl.h
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Let it return emulate state instead of spte like __direct_map
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Remove mmu_is_invalid and use is_invalid_pfn instead
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
There are no external callers of this function as there is no concept of
resetting a vcpu from generic code.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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Merge tag 'kvm-3.7-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Avi Kivity:
"Highlights of the changes for this release include support for vfio
level triggered interrupts, improved big real mode support on older
Intels, a streamlines guest page table walker, guest APIC speedups,
PIO optimizations, better overcommit handling, and read-only memory."
* tag 'kvm-3.7-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (138 commits)
KVM: s390: Fix vcpu_load handling in interrupt code
KVM: x86: Fix guest debug across vcpu INIT reset
KVM: Add resampling irqfds for level triggered interrupts
KVM: optimize apic interrupt delivery
KVM: MMU: Eliminate pointless temporary 'ac'
KVM: MMU: Avoid access/dirty update loop if all is well
KVM: MMU: Eliminate eperm temporary
KVM: MMU: Optimize is_last_gpte()
KVM: MMU: Simplify walk_addr_generic() loop
KVM: MMU: Optimize pte permission checks
KVM: MMU: Update accessed and dirty bits after guest pagetable walk
KVM: MMU: Move gpte_access() out of paging_tmpl.h
KVM: MMU: Optimize gpte_access() slightly
KVM: MMU: Push clean gpte write protection out of gpte_access()
KVM: clarify kvmclock documentation
KVM: make processes waiting on vcpu mutex killable
KVM: SVM: Make use of asm.h
KVM: VMX: Make use of asm.h
KVM: VMX: Make lto-friendly
KVM: x86: lapic: Clean up find_highest_vector() and count_vectors()
...
Conflicts:
arch/s390/include/asm/processor.h
arch/x86/kvm/i8259.c
Pull x86/fpu update from Ingo Molnar:
"The biggest change is the addition of the non-lazy (eager) FPU saving
support model and enabling it on CPUs with optimized xsaveopt/xrstor
FPU state saving instructions.
There are also various Sparse fixes"
Fix up trivial add-add conflict in arch/x86/kernel/traps.c
* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, kvm: fix kvm's usage of kernel_fpu_begin/end()
x86, fpu: remove cpu_has_xmm check in the fx_finit()
x86, fpu: make eagerfpu= boot param tri-state
x86, fpu: enable eagerfpu by default for xsaveopt
x86, fpu: decouple non-lazy/eager fpu restore from xsave
x86, fpu: use non-lazy fpu restore for processors supporting xsave
lguest, x86: handle guest TS bit for lazy/non-lazy fpu host models
x86, fpu: always use kernel_fpu_begin/end() for in-kernel FPU usage
x86, kvm: use kernel_fpu_begin/end() in kvm_load/put_guest_fpu()
x86, fpu: remove unnecessary user_fpu_end() in save_xstate_sig()
x86, fpu: drop_fpu() before restoring new state from sigframe
x86, fpu: Unify signal handling code paths for x86 and x86_64 kernels
x86, fpu: Consolidate inline asm routines for saving/restoring fpu state
x86, signal: Cleanup ifdefs and is_ia32, is_x32
Pull perf update from Ingo Molnar:
"Lots of changes in this cycle as well, with hundreds of commits from
over 30 contributors. Most of the activity was on the tooling side.
Higher level changes:
- New 'perf kvm' analysis tool, from Xiao Guangrong.
- New 'perf trace' system-wide tracing tool
- uprobes fixes + cleanups from Oleg Nesterov.
- Lots of patches to make perf build on Android out of box, from
Irina Tirdea
- Extend ftrace function tracing utility to be more dynamic for its
users. It allows for data passing to the callback functions, as
well as reading regs as if a breakpoint were to trigger at function
entry.
The main goal of this patch series was to allow kprobes to use
ftrace as an optimized probe point when a probe is placed on an
ftrace nop. With lots of help from Masami Hiramatsu, and going
through lots of iterations, we finally came up with a good
solution.
- Add cpumask for uncore pmu, use it in 'stat', from Yan, Zheng.
- Various tracing updates from Steve Rostedt
- Clean up and improve 'perf sched' performance by elliminating lots
of needless calls to libtraceevent.
- Event group parsing support, from Jiri Olsa
- UI/gtk refactorings and improvements from Namhyung Kim
- Add support for non-tracepoint events in perf script python, from
Feng Tang
- Add --symbols to 'script', similar to the one in 'report', from
Feng Tang.
Infrastructure enhancements and fixes:
- Convert the trace builtins to use the growing evsel/evlist
tracepoint infrastructure, removing several open coded constructs
like switch like series of strcmp to dispatch events, etc.
Basically what had already been showcased in 'perf sched'.
- Add evsel constructor for tracepoints, that uses libtraceevent just
to parse the /format events file, use it in a new 'perf test' to
make sure the libtraceevent format parsing regressions can be more
readily caught.
- Some strange errors were happening in some builds, but not on the
next, reported by several people, problem was some parser related
files, generated during the build, didn't had proper make deps, fix
from Eric Sandeen.
- Introduce struct and cache information about the environment where
a perf.data file was captured, from Namhyung Kim.
- Fix handling of unresolved samples when --symbols is used in
'report', from Feng Tang.
- Add union member access support to 'probe', from Hyeoncheol Lee.
- Fixups to die() removal, from Namhyung Kim.
- Render fixes for the TUI, from Namhyung Kim.
- Don't enable annotation in non symbolic view, from Namhyung Kim.
- Fix pipe mode in 'report', from Namhyung Kim.
- Move related stats code from stat to util/, will be used by the
'stat' kvm tool, from Xiao Guangrong.
- Remove die()/exit() calls from several tools.
- Resolve vdso callchains, from Jiri Olsa
- Don't pass const char pointers to basename, so that we can
unconditionally use libgen.h and thus avoid ifdef BIONIC lines,
from David Ahern
- Refactor hist formatting so that it can be reused with the GTK
browser, From Namhyung Kim
- Fix build for another rbtree.c change, from Adrian Hunter.
- Make 'perf diff' command work with evsel hists, from Jiri Olsa.
- Use the only field_sep var that is set up: symbol_conf.field_sep,
fix from Jiri Olsa.
- .gitignore compiled python binaries, from Namhyung Kim.
- Get rid of die() in more libtraceevent places, from Namhyung Kim.
- Rename libtraceevent 'private' struct member to 'priv' so that it
works in C++, from Steven Rostedt
- Remove lots of exit()/die() calls from tools so that the main perf
exit routine can take place, from David Ahern
- Fix x86 build on x86-64, from David Ahern.
- {int,str,rb}list fixes from Suzuki K Poulose
- perf.data header fixes from Namhyung Kim
- Allow user to indicate objdump path, needed in cross environments,
from Maciek Borzecki
- Fix hardware cache event name generation, fix from Jiri Olsa
- Add round trip test for sw, hw and cache event names, catching the
problem Jiri fixed, after Jiri's patch, the test passes
successfully.
- Clean target should do clean for lib/traceevent too, fix from David
Ahern
- Check the right variable for allocation failure, fix from Namhyung
Kim
- Set up evsel->tp_format regardless of evsel->name being set
already, fix from Namhyung Kim
- Oprofile fixes from Robert Richter.
- Remove perf_event_attr needless version inflation, from Jiri Olsa
- Introduce libtraceevent strerror like error reporting facility,
from Namhyung Kim
- Add pmu mappings to perf.data header and use event names from cmd
line, from Robert Richter
- Fix include order for bison/flex-generated C files, from Ben
Hutchings
- Build fixes and documentation corrections from David Ahern
- Assorted cleanups from Robert Richter
- Let O= makes handle relative paths, from Steven Rostedt
- perf script python fixes, from Feng Tang.
- Initial bash completion support, from Frederic Weisbecker
- Allow building without libelf, from Namhyung Kim.
- Support DWARF CFI based unwind to have callchains when %bp based
unwinding is not possible, from Jiri Olsa.
- Symbol resolution fixes, while fixing support PPC64 files with an
.opt ELF section was the end goal, several fixes for code that
handles all architectures and cleanups are included, from Cody
Schafer.
- Assorted fixes for Documentation and build in 32 bit, from Robert
Richter
- Cache the libtraceevent event_format associated to each evsel
early, so that we avoid relookups, i.e. calling pevent_find_event
repeatedly when processing tracepoint events.
[ This is to reduce the surface contact with libtraceevents and
make clear what is that the perf tools needs from that lib: so
far parsing the common and per event fields. ]
- Don't stop the build if the audit libraries are not installed, fix
from Namhyung Kim.
- Fix bfd.h/libbfd detection with recent binutils, from Markus
Trippelsdorf.
- Improve warning message when libunwind devel packages not present,
from Jiri Olsa"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (282 commits)
perf trace: Add aliases for some syscalls
perf probe: Print an enum type variable in "enum variable-name" format when showing accessible variables
perf tools: Check libaudit availability for perf-trace builtin
perf hists: Add missing period_* fields when collapsing a hist entry
perf trace: New tool
perf evsel: Export the event_format constructor
perf evsel: Introduce rawptr() method
perf tools: Use perf_evsel__newtp in the event parser
perf evsel: The tracepoint constructor should store sys:name
perf evlist: Introduce set_filter() method
perf evlist: Renane set_filters method to apply_filters
perf test: Add test to check we correctly parse and match syscall open parms
perf evsel: Handle endianity in intval method
perf evsel: Know if byte swap is needed
perf tools: Allow handling a NULL cpu_map as meaning "all cpus"
perf evsel: Improve tracepoint constructor setup
tools lib traceevent: Fix error path on pevent_parse_event
perf test: Fix build failure
trace: Move trace event enable from fs_initcall to core_initcall
tracing: Add an option for disabling markers
...
If we reset a vcpu on INIT, we so far overwrote dr7 as provided by
KVM_SET_GUEST_DEBUG, and we also cleared switch_db_regs unconditionally.
Fix this by saving the dr7 used for guest debugging and calculating the
effective register value as well as switch_db_regs on any potential
change. This will change to focus of the set_guest_debug vendor op to
update_dp_bp_intercept.
Found while trying to stop on start_secondary.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
To emulate level triggered interrupts, add a resample option to
KVM_IRQFD. When specified, a new resamplefd is provided that notifies
the user when the irqchip has been resampled by the VM. This may, for
instance, indicate an EOI. Also in this mode, posting of an interrupt
through an irqfd only asserts the interrupt. On resampling, the
interrupt is automatically de-asserted prior to user notification.
This enables level triggered interrupts to be posted and re-enabled
from vfio with no userspace intervention.
All resampling irqfds can make use of a single irq source ID, so we
reserve a new one for this interface.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Preemption is disabled between kernel_fpu_begin/end() and as such
it is not a good idea to use these routines in kvm_load/put_guest_fpu()
which can be very far apart.
kvm_load/put_guest_fpu() routines are already called with
preemption disabled and KVM already uses the preempt notifier to save
the guest fpu state using kvm_put_guest_fpu().
So introduce __kernel_fpu_begin/end() routines which don't touch
preemption and use them instead of kernel_fpu_begin/end()
for KVM's use model of saving/restoring guest FPU state.
Also with this change (and with eagerFPU model), fix the host cr0.TS vm-exit
state in the case of VMX. For eagerFPU case, host cr0.TS is always clear.
So no need to worry about it. For the traditional lazyFPU restore case,
change the cr0.TS bit for the host state during vm-exit to be always clear
and cr0.TS bit is set in the __vmx_load_host_state() when the FPU
(guest FPU or the host task's FPU) state is not active. This ensures
that the host/guest FPU state is properly saved, restored
during context-switch and with interrupts (using irq_fpu_usable()) not
stomping on the active FPU state.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1348164109.26695.338.camel@sbsiddha-desk.sc.intel.com
Cc: Avi Kivity <avi@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Exporting KVM exit information to userspace to be consumed by perf.
Signed-off-by: Dong Hao <haodong@linux.vnet.ibm.com>
[ Dong Hao <haodong@linux.vnet.ibm.com>: rebase it on acme's git tree ]
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: kvm@vger.kernel.org
Cc: Runzhen Wang <runzhen@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1347870675-31495-2-git-send-email-haodong@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Most interrupt are delivered to only one vcpu. Use pre-build tables to
find interrupt destination instead of looping through all vcpus. In case
of logical mode loop only through vcpus in a logical cluster irq is sent
to.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
'ac' essentially reconstructs the 'access' variable we already
have, except for the PFERR_PRESENT_MASK and PFERR_RSVD_MASK. As
these are not used by callees, just use 'access' directly.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Keep track of accessed/dirty bits; if they are all set, do not
enter the accessed/dirty update loop.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
'eperm' is no longer used in the walker loop, so we can eliminate it.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Instead of branchy code depending on level, gpte.ps, and mmu configuration,
prepare everything in a bitmap during mode changes and look it up during
runtime.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
The page table walk is coded as an infinite loop, with a special
case on the last pte.
Code it as an ordinary loop with a termination condition on the last
pte (large page or walk length exhausted), and put the last pte handling
code after the loop where it belongs.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
walk_addr_generic() permission checks are a maze of branchy code, which is
performed four times per lookup. It depends on the type of access, efer.nxe,
cr0.wp, cr4.smep, and in the near future, cr4.smap.
Optimize this away by precalculating all variants and storing them in a
bitmap. The bitmap is recalculated when rarely-changing variables change
(cr0, cr4) and is indexed by the often-changing variables (page fault error
code, pte access permissions).
The permission check is moved to the end of the loop, otherwise an SMEP
fault could be reported as a false positive, when PDE.U=1 but PTE.U=0.
Noted by Xiao Guangrong.
The result is short, branch-free code.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
While unspecified, the behaviour of Intel processors is to first
perform the page table walk, then, if the walk was successful, to
atomically update the accessed and dirty bits of walked paging elements.
While we are not required to follow this exactly, doing so will allow us
to perform the access permissions check after the walk is complete, rather
than after each walk step.
(the tricky case is SMEP: a zero in any pte's U bit makes the referenced
page a supervisor page, so we can't fault on a one bit during the walk
itself).
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
We no longer rely on paging_tmpl.h defines; so we can move the function
to mmu.c.
Rely on zero extension to 64 bits to get the correct nx behaviour.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
If nx is disabled, then is gpte[63] is set we will hit a reserved
bit set fault before checking permissions; so we can ignore the
setting of efer.nxe.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
gpte_access() computes the access permissions of a guest pte and also
write-protects clean gptes. This is wrong when we are servicing a
write fault (since we'll be setting the dirty bit momentarily) but
correct when instantiating a speculative spte, or when servicing a
read fault (since we'll want to trap a following write in order to
set the dirty bit).
It doesn't seem to hurt in practice, but in order to make the code
readable, push the write protection out of gpte_access() and into
a new protect_clean_gpte() which is called explicitly when needed.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
kvm's guest fpu save/restore should be wrapped around
kernel_fpu_begin/end(). This will avoid for example taking a DNA
in kvm_load_guest_fpu() when it tries to load the fpu immediately
after doing unlazy_fpu() on the host side.
More importantly this will prevent the host process fpu from being
corrupted.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1345842782-24175-4-git-send-email-suresh.b.siddha@intel.com
Cc: Avi Kivity <avi@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
vcpu mutex can be held for unlimited time so
taking it with mutex_lock on an ioctl is wrong:
one process could be passed a vcpu fd and
call this ioctl on the vcpu used by another process,
it will then be unkillable until the owner exits.
Call mutex_lock_killable instead and return status.
Note: mutex_lock_interruptible would be even nicer,
but I am not sure all users are prepared to handle EINTR
from these ioctls. They might misinterpret it as an error.
Cleanup paths expect a vcpu that can't be used by
any userspace so this will always succeed - catch bugs
by calling BUG_ON.
Catch callers that don't check return state by adding
__must_check.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Takuya Yoshikawa
Xiao Guangrong
Avi Kivity
Marcelo Tosatti
Gleb Natapov
Nickolai Zeldovich
Alex Williamson
Nadav Amit
Linus Torvalds
Zhang Yanfei
Julian Stecklina
Zhang Xiantao
Jan Kiszka
Will Auld
H. Peter Anvin
Takashi Iwai
Guo Chao
Petr Matousek
Christoffer Dall
Borislav Petkov
Suresh Siddha
Avi Kivity
Peter Senna Tschudin
Michael S. Tsirkin