From fe957b30ef5dd9e34ac057a48d8dad0b7ab5e574 Mon Sep 17 00:00:00 2001 From: Andrew Cooper Date: Fri, 20 Oct 2017 14:56:23 +0100 Subject: [PATCH] x86/vmx: Don't use rdmsr() to fill HOST_SYSENTER_{CS,EIP} These are compile-time constants, and don't need to be read back from hardware. Signed-off-by: Andrew Cooper Reviewed-by: Jan Beulich Acked-by: Kevin Tian --- xen/arch/x86/hvm/vmx/vmcs.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c index 6042109071..e7818caed0 100644 --- a/xen/arch/x86/hvm/vmx/vmcs.c +++ b/xen/arch/x86/hvm/vmx/vmcs.c @@ -994,8 +994,6 @@ static void pi_desc_init(struct vcpu *v) static int construct_vmcs(struct vcpu *v) { struct domain *d = v->domain; - uint16_t sysenter_cs; - unsigned long sysenter_eip; u32 vmexit_ctl = vmx_vmexit_control; u32 vmentry_ctl = vmx_vmentry_control; @@ -1155,10 +1153,8 @@ static int construct_vmcs(struct vcpu *v) __vmwrite(HOST_RIP, (unsigned long)vmx_asm_vmexit_handler); /* Host SYSENTER CS:RIP. */ - rdmsrl(MSR_IA32_SYSENTER_CS, sysenter_cs); - __vmwrite(HOST_SYSENTER_CS, sysenter_cs); - rdmsrl(MSR_IA32_SYSENTER_EIP, sysenter_eip); - __vmwrite(HOST_SYSENTER_EIP, sysenter_eip); + __vmwrite(HOST_SYSENTER_CS, __HYPERVISOR_CS); + __vmwrite(HOST_SYSENTER_EIP, (unsigned long)sysenter_entry); /* MSR intercepts. */ __vmwrite(VM_EXIT_MSR_LOAD_COUNT, 0); -- 2.30.2