microsoft
/
WSL2-Linux-Kernel
зеркало из https://github.com/microsoft/WSL2-Linux-Kernel.git
1
0
Форкнуть 0
Код Задачи Пакеты Проекты Релизы Вики Активность

KVM: PPC: Book3S 64: Move GUEST_MODE_SKIP test into KVM 

Move the GUEST_MODE_SKIP logic into KVM code. This is quite a KVM
internal detail that has no real need to be in common handlers.

Add a comment explaining the what and why of KVM "skip" interrupts.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210528090752.3542186-3-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2021-05-28 19:07:22 +10:00 коммит произвёл Michael Ellerman
Родитель f36011569b
Коммит f33e0702d9
2 изменённых файлов: 58 добавлений и 61 удалений
Показать статистику Скачать Patch файл Скачать Diff файл Показать все файлы Свернуть все файлы

60
arch/powerpc/kernel/exceptions-64s.S
Просмотреть файл

@ -133,7 +133,6 @@ name:
#define IBRANCH_TO_COMMON .L_IBRANCH_TO_COMMON_\name\() /* ENTRY branch to common */ #define IBRANCH_TO_COMMON .L_IBRANCH_TO_COMMON_\name\() /* ENTRY branch to common */
#define IREALMODE_COMMON .L_IREALMODE_COMMON_\name\() /* Common runs in realmode */ #define IREALMODE_COMMON .L_IREALMODE_COMMON_\name\() /* Common runs in realmode */
#define IMASK .L_IMASK_\name\() /* IRQ soft-mask bit */ #define IMASK .L_IMASK_\name\() /* IRQ soft-mask bit */
#define IKVM_SKIP .L_IKVM_SKIP_\name\() /* Generate KVM skip handler */
#define IKVM_REAL .L_IKVM_REAL_\name\() /* Real entry tests KVM */ #define IKVM_REAL .L_IKVM_REAL_\name\() /* Real entry tests KVM */
#define __IKVM_REAL(name) .L_IKVM_REAL_ ## name #define __IKVM_REAL(name) .L_IKVM_REAL_ ## name
#define IKVM_VIRT .L_IKVM_VIRT_\name\() /* Virt entry tests KVM */ #define IKVM_VIRT .L_IKVM_VIRT_\name\() /* Virt entry tests KVM */
@ -190,9 +189,6 @@ do_define_int n
.ifndef IMASK .ifndef IMASK
IMASK=0 IMASK=0
.endif .endif
.ifndef IKVM_SKIP
IKVM_SKIP=0
.endif
.ifndef IKVM_REAL .ifndef IKVM_REAL
IKVM_REAL=0 IKVM_REAL=0
.endif .endif
@ -250,15 +246,10 @@ do_define_int n
.balign IFETCH_ALIGN_BYTES .balign IFETCH_ALIGN_BYTES
\name\()_kvm: \name\()_kvm:
.if IKVM_SKIP
cmpwi r10,KVM_GUEST_MODE_SKIP
beq 89f
.else
BEGIN_FTR_SECTION BEGIN_FTR_SECTION
ld r10,IAREA+EX_CFAR(r13) ld r10,IAREA+EX_CFAR(r13)
std r10,HSTATE_CFAR(r13) std r10,HSTATE_CFAR(r13)
END_FTR_SECTION_IFSET(CPU_FTR_CFAR) END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
.endif
ld r10,IAREA+EX_CTR(r13) ld r10,IAREA+EX_CTR(r13)
mtctr r10 mtctr r10
@ -285,27 +276,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
ori r12,r12,(IVEC) ori r12,r12,(IVEC)
.endif .endif
b kvmppc_interrupt b kvmppc_interrupt
.if IKVM_SKIP
89: mtocrf 0x80,r9
ld r10,IAREA+EX_CTR(r13)
mtctr r10
ld r9,IAREA+EX_R9(r13)
ld r10,IAREA+EX_R10(r13)
ld r11,IAREA+EX_R11(r13)
ld r12,IAREA+EX_R12(r13)
.if IHSRR_IF_HVMODE
BEGIN_FTR_SECTION
b kvmppc_skip_Hinterrupt
FTR_SECTION_ELSE
b kvmppc_skip_interrupt
ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_206)
.elseif IHSRR
b kvmppc_skip_Hinterrupt
.else
b kvmppc_skip_interrupt
.endif
.endif
.endm .endm
#else #else
@ -1064,7 +1034,6 @@ INT_DEFINE_BEGIN(machine_check)
ISET_RI=0 ISET_RI=0
IDAR=1 IDAR=1
IDSISR=1 IDSISR=1
IKVM_SKIP=1
IKVM_REAL=1 IKVM_REAL=1
INT_DEFINE_END(machine_check) INT_DEFINE_END(machine_check)
@ -1336,7 +1305,6 @@ INT_DEFINE_BEGIN(data_access)
IVEC=0x300 IVEC=0x300
IDAR=1 IDAR=1
IDSISR=1 IDSISR=1
IKVM_SKIP=1
IKVM_REAL=1 IKVM_REAL=1
INT_DEFINE_END(data_access) INT_DEFINE_END(data_access)
@ -1390,7 +1358,6 @@ ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX)
INT_DEFINE_BEGIN(data_access_slb) INT_DEFINE_BEGIN(data_access_slb)
IVEC=0x380 IVEC=0x380
IDAR=1 IDAR=1
IKVM_SKIP=1
IKVM_REAL=1 IKVM_REAL=1
INT_DEFINE_END(data_access_slb) INT_DEFINE_END(data_access_slb)
@ -2057,7 +2024,6 @@ INT_DEFINE_BEGIN(h_data_storage)
IHSRR=1 IHSRR=1
IDAR=1 IDAR=1
IDSISR=1 IDSISR=1
IKVM_SKIP=1
IKVM_REAL=1 IKVM_REAL=1
IKVM_VIRT=1 IKVM_VIRT=1
INT_DEFINE_END(h_data_storage) INT_DEFINE_END(h_data_storage)
@ -3003,32 +2969,6 @@ EXPORT_SYMBOL(do_uaccess_flush)
MASKED_INTERRUPT MASKED_INTERRUPT
MASKED_INTERRUPT hsrr=1 MASKED_INTERRUPT hsrr=1
#ifdef CONFIG_KVM_BOOK3S_64_HANDLER
kvmppc_skip_interrupt:
/*
* Here all GPRs are unchanged from when the interrupt happened
* except for r13, which is saved in SPRG_SCRATCH0.
*/
mfspr r13, SPRN_SRR0
addi r13, r13, 4
mtspr SPRN_SRR0, r13
GET_SCRATCH0(r13)
RFI_TO_KERNEL
b .
kvmppc_skip_Hinterrupt:
/*
* Here all GPRs are unchanged from when the interrupt happened
* except for r13, which is saved in SPRG_SCRATCH0.
*/
mfspr r13, SPRN_HSRR0
addi r13, r13, 4
mtspr SPRN_HSRR0, r13
GET_SCRATCH0(r13)
HRFI_TO_KERNEL
b .
#endif
/* /*
* Relocation-on interrupts: A subset of the interrupts can be delivered * Relocation-on interrupts: A subset of the interrupts can be delivered
* with IR=1/DR=1, if AIL==2 and MSR.HV won't be changed by delivering * with IR=1/DR=1, if AIL==2 and MSR.HV won't be changed by delivering

59
arch/powerpc/kvm/book3s_64_entry.S
Просмотреть файл

@ -1,6 +1,7 @@
/* SPDX-License-Identifier: GPL-2.0-only */ /* SPDX-License-Identifier: GPL-2.0-only */
#include <asm/asm-offsets.h> #include <asm/asm-offsets.h>
#include <asm/cache.h> #include <asm/cache.h>
#include <asm/exception-64s.h>
#include <asm/kvm_asm.h> #include <asm/kvm_asm.h>
#include <asm/kvm_book3s_asm.h> #include <asm/kvm_book3s_asm.h>
#include <asm/ppc_asm.h> #include <asm/ppc_asm.h>
@ -20,9 +21,12 @@ kvmppc_interrupt:
* guest R12 saved in shadow VCPU SCRATCH0 * guest R12 saved in shadow VCPU SCRATCH0
* guest R13 saved in SPRN_SCRATCH0 * guest R13 saved in SPRN_SCRATCH0
*/ */
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
std r9,HSTATE_SCRATCH2(r13) std r9,HSTATE_SCRATCH2(r13)
lbz r9,HSTATE_IN_GUEST(r13) lbz r9,HSTATE_IN_GUEST(r13)
cmpwi r9,KVM_GUEST_MODE_SKIP
beq- .Lmaybe_skip
.Lno_skip:
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
cmpwi r9,KVM_GUEST_MODE_HOST_HV cmpwi r9,KVM_GUEST_MODE_HOST_HV
beq kvmppc_bad_host_intr beq kvmppc_bad_host_intr
#ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE #ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
@ -32,5 +36,58 @@ kvmppc_interrupt:
#endif #endif
b kvmppc_interrupt_hv b kvmppc_interrupt_hv
#else #else
ld r9,HSTATE_SCRATCH2(r13)
b kvmppc_interrupt_pr b kvmppc_interrupt_pr
#endif #endif
/*
* "Skip" interrupts are part of a trick KVM uses a with hash guests to load
* the faulting instruction in guest memory from the the hypervisor without
* walking page tables.
*
* When the guest takes a fault that requires the hypervisor to load the
* instruction (e.g., MMIO emulation), KVM is running in real-mode with HV=1
* and the guest MMU context loaded. It sets KVM_GUEST_MODE_SKIP, and sets
* MSR[DR]=1 while leaving MSR[IR]=0, so it continues to fetch HV instructions
* but loads and stores will access the guest context. This is used to load
* the faulting instruction using the faulting guest effective address.
*
* However the guest context may not be able to translate, or it may cause a
* machine check or other issue, which results in a fault in the host
* (even with KVM-HV).
*
* These faults come here because KVM_GUEST_MODE_SKIP was set, so if they
* are (or are likely) caused by that load, the instruction is skipped by
* just returning with the PC advanced +4, where it is noticed the load did
* not execute and it goes to the slow path which walks the page tables to
* read guest memory.
*/
.Lmaybe_skip:
cmpwi r12,BOOK3S_INTERRUPT_MACHINE_CHECK
beq 1f
cmpwi r12,BOOK3S_INTERRUPT_DATA_STORAGE
beq 1f
cmpwi r12,BOOK3S_INTERRUPT_DATA_SEGMENT
beq 1f
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
/* HSRR interrupts get 2 added to interrupt number */
cmpwi r12,BOOK3S_INTERRUPT_H_DATA_STORAGE | 0x2
beq 2f
#endif
b .Lno_skip
1: mfspr r9,SPRN_SRR0
addi r9,r9,4
mtspr SPRN_SRR0,r9
ld r12,HSTATE_SCRATCH0(r13)
ld r9,HSTATE_SCRATCH2(r13)
GET_SCRATCH0(r13)
RFI_TO_KERNEL
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
2: mfspr r9,SPRN_HSRR0
addi r9,r9,4
mtspr SPRN_HSRR0,r9
ld r12,HSTATE_SCRATCH0(r13)
ld r9,HSTATE_SCRATCH2(r13)
GET_SCRATCH0(r13)
HRFI_TO_KERNEL
#endif