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| author | Avi Kivity <avi@qumranet.com> | 2008-07-17 18:04:30 +0300 |
|---|---|---|
| committer | Avi Kivity <avi@qumranet.com> | 2008-10-15 10:15:15 +0200 |
| commit | 313dbd49dc239205b96da79fba09f7637cf84f3c (patch) | |
| tree | 4cc4989b88d23d9e351acd4759378774e789905c /arch/x86/kvm/vmx.c | |
| parent | 3b4bd7969f7b61a1ab455bff084ee4f0a2411055 (diff) | |
| download | lwn-313dbd49dc239205b96da79fba09f7637cf84f3c.tar.gz lwn-313dbd49dc239205b96da79fba09f7637cf84f3c.zip | |
KVM: VMX: Avoid vmwrite(HOST_RSP) when possible
Usually HOST_RSP retains its value across guest entries. Take advantage
of this and avoid a vmwrite() when this is so.
Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'arch/x86/kvm/vmx.c')
| -rw-r--r-- | arch/x86/kvm/vmx.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index fc8996b1043b..ddb49e34697b 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -58,6 +58,7 @@ struct vmcs { struct vcpu_vmx { struct kvm_vcpu vcpu; struct list_head local_vcpus_link; + unsigned long host_rsp; int launched; u8 fail; u32 idt_vectoring_info; @@ -2982,7 +2983,11 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) /* Store host registers */ "push %%"R"dx; push %%"R"bp;" "push %%"R"cx \n\t" + "cmp %%"R"sp, %c[host_rsp](%0) \n\t" + "je 1f \n\t" + "mov %%"R"sp, %c[host_rsp](%0) \n\t" __ex(ASM_VMX_VMWRITE_RSP_RDX) "\n\t" + "1: \n\t" /* Check if vmlaunch of vmresume is needed */ "cmpl $0, %c[launched](%0) \n\t" /* Load guest registers. Don't clobber flags. */ @@ -3039,6 +3044,7 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) : : "c"(vmx), "d"((unsigned long)HOST_RSP), [launched]"i"(offsetof(struct vcpu_vmx, launched)), [fail]"i"(offsetof(struct vcpu_vmx, fail)), + [host_rsp]"i"(offsetof(struct vcpu_vmx, host_rsp)), [rax]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_RAX])), [rbx]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_RBX])), [rcx]"i"(offsetof(struct vcpu_vmx, vcpu.arch.regs[VCPU_REGS_RCX])), |