From b3dbf89e676e47ef3b10802f9aba5a8e04aba132 Mon Sep 17 00:00:00 2001
From: Avi Kivity <avi@redhat.com>
Date: Tue, 16 Jun 2009 12:36:33 +0300
Subject: [PATCH] KVM: SVM: Don't save/restore host cr2
The host never reads cr2 in process context, so are free to clobber it. The
vmx code does this, so we can safely remove the save/restore code.
Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/x86/kvm/svm.c | 17 -----------------
1 file changed, 17 deletions(-)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 060aa9f5571e..132be0c7c3eb 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -81,7 +81,6 @@ struct vcpu_svm {
u64 host_user_msrs[NR_HOST_SAVE_USER_MSRS];
u64 host_gs_base;
- unsigned long host_cr2;
u32 *msrpm;
struct vmcb *hsave;
@@ -186,19 +185,6 @@ static inline void invlpga(unsigned long addr, u32 asid)
asm volatile (__ex(SVM_INVLPGA) :: "a"(addr), "c"(asid));
}
-static inline unsigned long kvm_read_cr2(void)
-{
- unsigned long cr2;
-
- asm volatile ("mov %%cr2, %0" : "=r" (cr2));
- return cr2;
-}
-
-static inline void kvm_write_cr2(unsigned long val)
-{
- asm volatile ("mov %0, %%cr2" :: "r" (val));
-}
-
static inline void force_new_asid(struct kvm_vcpu *vcpu)
{
to_svm(vcpu)->asid_generation--;
@@ -2527,7 +2513,6 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
fs_selector = kvm_read_fs();
gs_selector = kvm_read_gs();
ldt_selector = kvm_read_ldt();
- svm->host_cr2 = kvm_read_cr2();
if (!is_nested(svm))
svm->vmcb->save.cr2 = vcpu->arch.cr2;
/* required for live migration with NPT */
@@ -2614,8 +2599,6 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
vcpu->arch.regs[VCPU_REGS_RSP] = svm->vmcb->save.rsp;
vcpu->arch.regs[VCPU_REGS_RIP] = svm->vmcb->save.rip;
- kvm_write_cr2(svm->host_cr2);
-
kvm_load_fs(fs_selector);
kvm_load_gs(gs_selector);
kvm_load_ldt(ldt_selector);
--
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