From 12a056ebf39c7c0ed09b6b0739fb4de237be1144 Mon Sep 17 00:00:00 2001 From: "kfraser@localhost.localdomain" Date: Tue, 15 May 2007 10:46:03 +0100 Subject: [PATCH] vmx: remove CSTAR save/restore on VMX CSTAR is an unused MSR in 64-bit mode on Intel's EM64T, hence there's no need to save/restore this MSR during context switches. Mimic real hardware by retaining the value written for eventual guest OS reads. Signed-off-by: Jan Beulich --- xen/arch/x86/hvm/vmx/vmx.c | 12 ++++++------ xen/include/asm-x86/hvm/vmx/vmcs.h | 2 +- 2 files changed, 7 insertions(+), 7 deletions(-) diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c index a0d64aa41f..931e951b0b 100644 --- a/xen/arch/x86/hvm/vmx/vmx.c +++ b/xen/arch/x86/hvm/vmx/vmx.c @@ -88,8 +88,7 @@ static DEFINE_PER_CPU(struct vmx_msr_state, host_msr_state); static u32 msr_index[VMX_MSR_COUNT] = { - MSR_LSTAR, MSR_STAR, MSR_CSTAR, - MSR_SYSCALL_MASK + MSR_LSTAR, MSR_STAR, MSR_SYSCALL_MASK }; static void vmx_save_host_msrs(void) @@ -146,7 +145,7 @@ static inline int long_mode_do_msr_read(struct cpu_user_regs *regs) break; case MSR_CSTAR: - msr_content = guest_msr_state->msrs[VMX_INDEX_MSR_CSTAR]; + msr_content = v->arch.hvm_vmx.cstar; break; case MSR_SYSCALL_MASK: @@ -249,7 +248,8 @@ static inline int long_mode_do_msr_write(struct cpu_user_regs *regs) case MSR_CSTAR: if ( !is_canonical_address(msr_content) ) goto uncanonical_address; - WRITE_MSR(CSTAR); + v->arch.hvm_vmx.cstar = msr_content; + break; case MSR_SYSCALL_MASK: WRITE_MSR(SYSCALL_MASK); @@ -729,12 +729,12 @@ static void vmx_save_cpu_state(struct vcpu *v, struct hvm_hw_cpu *data) unsigned long guest_flags = guest_state->flags; data->shadow_gs = v->arch.hvm_vmx.shadow_gs; + data->msr_cstar = v->arch.hvm_vmx.cstar; /* save msrs */ data->msr_flags = guest_flags; data->msr_lstar = guest_state->msrs[VMX_INDEX_MSR_LSTAR]; data->msr_star = guest_state->msrs[VMX_INDEX_MSR_STAR]; - data->msr_cstar = guest_state->msrs[VMX_INDEX_MSR_CSTAR]; data->msr_syscall_mask = guest_state->msrs[VMX_INDEX_MSR_SYSCALL_MASK]; #endif @@ -754,9 +754,9 @@ static void vmx_load_cpu_state(struct vcpu *v, struct hvm_hw_cpu *data) guest_state->flags = data->msr_flags; guest_state->msrs[VMX_INDEX_MSR_LSTAR] = data->msr_lstar; guest_state->msrs[VMX_INDEX_MSR_STAR] = data->msr_star; - guest_state->msrs[VMX_INDEX_MSR_CSTAR] = data->msr_cstar; guest_state->msrs[VMX_INDEX_MSR_SYSCALL_MASK] = data->msr_syscall_mask; + v->arch.hvm_vmx.cstar = data->msr_cstar; v->arch.hvm_vmx.shadow_gs = data->shadow_gs; #endif diff --git a/xen/include/asm-x86/hvm/vmx/vmcs.h b/xen/include/asm-x86/hvm/vmx/vmcs.h index 839f450d39..8584a8d3db 100644 --- a/xen/include/asm-x86/hvm/vmx/vmcs.h +++ b/xen/include/asm-x86/hvm/vmx/vmcs.h @@ -37,7 +37,6 @@ struct vmcs_struct { enum { VMX_INDEX_MSR_LSTAR = 0, VMX_INDEX_MSR_STAR, - VMX_INDEX_MSR_CSTAR, VMX_INDEX_MSR_SYSCALL_MASK, VMX_MSR_COUNT @@ -77,6 +76,7 @@ struct arch_vmx_struct { #ifdef __x86_64__ struct vmx_msr_state msr_state; unsigned long shadow_gs; + unsigned long cstar; #endif unsigned long efer; unsigned long vmxassist_enabled:1; -- 2.30.2