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KVM: SVM: Add xsetbv intercept

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This patch implements the xsetbv intercept to the AMD part
of KVM. This makes AVX usable in a save way for the guest on
AVX capable AMD hardware.

The patch is tested by using AVX in the guest and host in
parallel and checking for data corruption. I also used the
KVM xsave unit-tests and they all pass.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Joerg Roedel 2010-12-07 17:15:06 +01:00 committed by Avi Kivity
parent d4dbf47009
commit 81dd35d42c
2 changed files with 18 additions and 4 deletions
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2
arch/x86/include/asm/svm.h
View file

@ -47,6 +47,7 @@ enum {
INTERCEPT_MONITOR,
INTERCEPT_MWAIT,
INTERCEPT_MWAIT_COND,
INTERCEPT_XSETBV,
};
@ -329,6 +330,7 @@ struct __attribute__ ((__packed__)) vmcb {
#define SVM_EXIT_MONITOR 0x08a
#define SVM_EXIT_MWAIT 0x08b
#define SVM_EXIT_MWAIT_COND 0x08c
#define SVM_EXIT_XSETBV 0x08d
#define SVM_EXIT_NPF 0x400
#define SVM_EXIT_ERR -1

20
arch/x86/kvm/svm.c
View file

@ -935,6 +935,7 @@ static void init_vmcb(struct vcpu_svm *svm)
set_intercept(svm, INTERCEPT_WBINVD);
set_intercept(svm, INTERCEPT_MONITOR);
set_intercept(svm, INTERCEPT_MWAIT);
set_intercept(svm, INTERCEPT_XSETBV);
control->iopm_base_pa = iopm_base;
control->msrpm_base_pa = __pa(svm->msrpm);
@ -2546,6 +2547,19 @@ static int skinit_interception(struct vcpu_svm *svm)
return 1;
}
static int xsetbv_interception(struct vcpu_svm *svm)
{
u64 new_bv = kvm_read_edx_eax(&svm->vcpu);
u32 index = kvm_register_read(&svm->vcpu, VCPU_REGS_RCX);
if (kvm_set_xcr(&svm->vcpu, index, new_bv) == 0) {
svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;
skip_emulated_instruction(&svm->vcpu);
}
return 1;
}
static int invalid_op_interception(struct vcpu_svm *svm)
{
kvm_queue_exception(&svm->vcpu, UD_VECTOR);
@ -2971,6 +2985,7 @@ static int (*svm_exit_handlers[])(struct vcpu_svm *svm) = {
[SVM_EXIT_WBINVD] = emulate_on_interception,
[SVM_EXIT_MONITOR] = invalid_op_interception,
[SVM_EXIT_MWAIT] = invalid_op_interception,
[SVM_EXIT_XSETBV] = xsetbv_interception,
[SVM_EXIT_NPF] = pf_interception,
};
@ -3624,10 +3639,6 @@ static void svm_cpuid_update(struct kvm_vcpu *vcpu)
static void svm_set_supported_cpuid(u32 func, struct kvm_cpuid_entry2 *entry)
{
switch (func) {
case 0x00000001:
/* Mask out xsave bit as long as it is not supported by SVM */
entry->ecx &= ~(bit(X86_FEATURE_XSAVE));
break;
case 0x80000001:
if (nested)
entry->ecx |= (1 << 2); /* Set SVM bit */
@ -3701,6 +3712,7 @@ static const struct trace_print_flags svm_exit_reasons_str[] = {
{ SVM_EXIT_WBINVD, "wbinvd" },
{ SVM_EXIT_MONITOR, "monitor" },
{ SVM_EXIT_MWAIT, "mwait" },
{ SVM_EXIT_XSETBV, "xsetbv" },
{ SVM_EXIT_NPF, "npf" },
{ -1, NULL }
};