From 6efa20e49b9cb1db1ab66870cc37323474a75a13 Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Fri, 19 Jul 2013 11:51:31 -0400 Subject: [PATCH] xen: Support 64-bit PV guest receiving NMIs This is based on a patch that Zhenzhong Duan had sent - which was missing some of the remaining pieces. The kernel has the logic to handle Xen-type-exceptions using the paravirt interface in the assembler code (see PARAVIRT_ADJUST_EXCEPTION_FRAME - pv_irq_ops.adjust_exception_frame and and INTERRUPT_RETURN - pv_cpu_ops.iret). That means the nmi handler (and other exception handlers) use the hypervisor iret. The other changes that would be neccessary for this would be to translate the NMI_VECTOR to one of the entries on the ipi_vector and make xen_send_IPI_mask_allbutself use different events. Fortunately for us commit 1db01b4903639fcfaec213701a494fe3fb2c490b (xen: Clean up apic ipi interface) implemented this and we piggyback on the cleanup such that the apic IPI interface will pass the right vector value for NMI. With this patch we can trigger NMIs within a PV guest (only tested x86_64). For this to work with normal PV guests (not initial domain) we need the domain to be able to use the APIC ops - they are already implemented to use the Xen event channels. For that to be turned on in a PV domU we need to remove the masking of X86_FEATURE_APIC. Incidentally that means kgdb will also now work within a PV guest without using the 'nokgdbroundup' workaround. Note that the 32-bit version is different and this patch does not enable that. CC: Lisa Nguyen CC: Ben Guthro CC: Zhenzhong Duan Signed-off-by: Konrad Rzeszutek Wilk [v1: Fixed up per David Vrabel comments] Reviewed-by: Ben Guthro Reviewed-by: David Vrabel --- arch/x86/include/asm/xen/events.h | 1 + arch/x86/xen/enlighten.c | 13 ++++++++----- arch/x86/xen/setup.c | 13 +++++++++++-- arch/x86/xen/smp.c | 6 ++++++ drivers/xen/events.c | 11 ++++++++++- include/xen/interface/vcpu.h | 2 ++ 6 files changed, 38 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/xen/events.h b/arch/x86/include/asm/xen/events.h index ca842f2769ef..608a79d5a466 100644 --- a/arch/x86/include/asm/xen/events.h +++ b/arch/x86/include/asm/xen/events.h @@ -7,6 +7,7 @@ enum ipi_vector { XEN_CALL_FUNCTION_SINGLE_VECTOR, XEN_SPIN_UNLOCK_VECTOR, XEN_IRQ_WORK_VECTOR, + XEN_NMI_VECTOR, XEN_NR_IPIS, }; diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 193097ef3d7d..b5a22fa7e249 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -427,8 +427,7 @@ static void __init xen_init_cpuid_mask(void) if (!xen_initial_domain()) cpuid_leaf1_edx_mask &= - ~((1 << X86_FEATURE_APIC) | /* disable local APIC */ - (1 << X86_FEATURE_ACPI)); /* disable ACPI */ + ~((1 << X86_FEATURE_ACPI)); /* disable ACPI */ cpuid_leaf1_ecx_mask &= ~(1 << (X86_FEATURE_X2APIC % 32)); @@ -735,8 +734,7 @@ static int cvt_gate_to_trap(int vector, const gate_desc *val, addr = (unsigned long)xen_int3; else if (addr == (unsigned long)stack_segment) addr = (unsigned long)xen_stack_segment; - else if (addr == (unsigned long)double_fault || - addr == (unsigned long)nmi) { + else if (addr == (unsigned long)double_fault) { /* Don't need to handle these */ return 0; #ifdef CONFIG_X86_MCE @@ -747,7 +745,12 @@ static int cvt_gate_to_trap(int vector, const gate_desc *val, */ ; #endif - } else { + } else if (addr == (unsigned long)nmi) + /* + * Use the native version as well. + */ + ; + else { /* Some other trap using IST? */ if (WARN_ON(val->ist != 0)) return 0; diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index 056d11faef21..403f5cc5415b 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -33,6 +33,9 @@ /* These are code, but not functions. Defined in entry.S */ extern const char xen_hypervisor_callback[]; extern const char xen_failsafe_callback[]; +#ifdef CONFIG_X86_64 +extern const char nmi[]; +#endif extern void xen_sysenter_target(void); extern void xen_syscall_target(void); extern void xen_syscall32_target(void); @@ -525,7 +528,13 @@ void xen_enable_syscall(void) } #endif /* CONFIG_X86_64 */ } - +void __cpuinit xen_enable_nmi(void) +{ +#ifdef CONFIG_X86_64 + if (register_callback(CALLBACKTYPE_nmi, nmi)) + BUG(); +#endif +} void __init xen_arch_setup(void) { xen_panic_handler_init(); @@ -543,7 +552,7 @@ void __init xen_arch_setup(void) xen_enable_sysenter(); xen_enable_syscall(); - + xen_enable_nmi(); #ifdef CONFIG_ACPI if (!(xen_start_info->flags & SIF_INITDOMAIN)) { printk(KERN_INFO "ACPI in unprivileged domain disabled\n"); diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index ca92754eb846..22759c6d309f 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -572,6 +572,12 @@ static inline int xen_map_vector(int vector) case IRQ_WORK_VECTOR: xen_vector = XEN_IRQ_WORK_VECTOR; break; +#ifdef CONFIG_X86_64 + case NMI_VECTOR: + case APIC_DM_NMI: /* Some use that instead of NMI_VECTOR */ + xen_vector = XEN_NMI_VECTOR; + break; +#endif default: xen_vector = -1; printk(KERN_ERR "xen: vector 0x%x is not implemented\n", diff --git a/drivers/xen/events.c b/drivers/xen/events.c index a58ac435a9a4..c8b9d9fc77b5 100644 --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -56,6 +56,7 @@ #include #include #include +#include #include /* @@ -1212,7 +1213,15 @@ EXPORT_SYMBOL_GPL(evtchn_put); void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector) { - int irq = per_cpu(ipi_to_irq, cpu)[vector]; + int irq; + + if (unlikely(vector == XEN_NMI_VECTOR)) { + int rc = HYPERVISOR_vcpu_op(VCPUOP_send_nmi, cpu, NULL); + if (rc < 0) + printk(KERN_WARNING "Sending nmi to CPU%d failed (rc:%d)\n", cpu, rc); + return; + } + irq = per_cpu(ipi_to_irq, cpu)[vector]; BUG_ON(irq < 0); notify_remote_via_irq(irq); } diff --git a/include/xen/interface/vcpu.h b/include/xen/interface/vcpu.h index 87e6f8a48661..b05288ce3991 100644 --- a/include/xen/interface/vcpu.h +++ b/include/xen/interface/vcpu.h @@ -170,4 +170,6 @@ struct vcpu_register_vcpu_info { }; DEFINE_GUEST_HANDLE_STRUCT(vcpu_register_vcpu_info); +/* Send an NMI to the specified VCPU. @extra_arg == NULL. */ +#define VCPUOP_send_nmi 11 #endif /* __XEN_PUBLIC_VCPU_H__ */