From 94dfbdb3894eda2f673b70e20da2743c4a8d3968 Mon Sep 17 00:00:00 2001 From: Anthony Liguori Date: Sun, 29 Apr 2007 11:56:06 +0300 Subject: KVM: SVM: Only save/restore MSRs when needed We only have to save/restore MSR_GS_BASE on every VMEXIT. The rest can be saved/restored when we leave the VCPU. Since we don't emulate the DEBUGCTL MSRs and the guest cannot write to them, we don't have to worry about saving/restoring them at all. This shaves a whopping 40% off raw vmexit costs on AMD. Signed-off-by: Anthony Liguori Signed-off-by: Avi Kivity --- drivers/kvm/kvm_svm.h | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) (limited to 'drivers/kvm/kvm_svm.h') diff --git a/drivers/kvm/kvm_svm.h b/drivers/kvm/kvm_svm.h index a1a9eba..a869983 100644 --- a/drivers/kvm/kvm_svm.h +++ b/drivers/kvm/kvm_svm.h @@ -9,17 +9,15 @@ #include "svm.h" #include "kvm.h" -static const u32 host_save_msrs[] = { +static const u32 host_save_user_msrs[] = { #ifdef CONFIG_X86_64 MSR_STAR, MSR_LSTAR, MSR_CSTAR, MSR_SYSCALL_MASK, MSR_KERNEL_GS_BASE, - MSR_FS_BASE, MSR_GS_BASE, + MSR_FS_BASE, #endif MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP, - MSR_IA32_DEBUGCTLMSR, /*MSR_IA32_LASTBRANCHFROMIP, - MSR_IA32_LASTBRANCHTOIP, MSR_IA32_LASTINTFROMIP,MSR_IA32_LASTINTTOIP,*/ }; -#define NR_HOST_SAVE_MSRS ARRAY_SIZE(host_save_msrs) +#define NR_HOST_SAVE_USER_MSRS ARRAY_SIZE(host_save_user_msrs) #define NUM_DB_REGS 4 struct vcpu_svm { @@ -32,7 +30,8 @@ struct vcpu_svm { u64 next_rip; - u64 host_msrs[NR_HOST_SAVE_MSRS]; + u64 host_user_msrs[NR_HOST_SAVE_USER_MSRS]; + u64 host_gs_base; unsigned long host_cr2; unsigned long host_db_regs[NUM_DB_REGS]; unsigned long host_dr6; -- cgit v1.1