KVM: VMX: Enable XSAVE/XRSTOR for guest

This patch enable guest to use XSAVE/XRSTOR instructions.

We assume that host_xcr0 would use all possible bits that OS supported.

And we loaded xcr0 in the same way we handled fpu - do it as late as we can.

Signed-off-by: Dexuan Cui <dexuan.cui@intel.com>
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 26ba61d6af8c..864a1b6d155a 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -37,6 +37,8 @@
 #include <asm/vmx.h>
 #include <asm/virtext.h>
 #include <asm/mce.h>
+#include <asm/i387.h>
+#include <asm/xcr.h>
 
 #include "trace.h"
 
@@ -3390,6 +3392,16 @@ static int handle_wbinvd(struct kvm_vcpu *vcpu)
         return 1;
 }
 
+static int handle_xsetbv(struct kvm_vcpu *vcpu)
+{
+        u64 new_bv = kvm_read_edx_eax(vcpu);
+        u32 index = kvm_register_read(vcpu, VCPU_REGS_RCX);
+
+        if (kvm_set_xcr(vcpu, index, new_bv) == 0)
+                skip_emulated_instruction(vcpu);
+        return 1;
+}
+
 static int handle_apic_access(struct kvm_vcpu *vcpu)
 {
         return emulate_instruction(vcpu, 0, 0, 0) == EMULATE_DONE;
@@ -3668,6 +3680,7 @@ static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = {
         [EXIT_REASON_TPR_BELOW_THRESHOLD]     = handle_tpr_below_threshold,
         [EXIT_REASON_APIC_ACCESS]             = handle_apic_access,
         [EXIT_REASON_WBINVD]                  = handle_wbinvd,
+        [EXIT_REASON_XSETBV]                  = handle_xsetbv,
         [EXIT_REASON_TASK_SWITCH]             = handle_task_switch,
         [EXIT_REASON_MCE_DURING_VMENTRY]      = handle_machine_check,
         [EXIT_REASON_EPT_VIOLATION]           = handle_ept_violation,