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target/i386: kvm: initialize feature MSRs very early

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Some read-only MSRs affect the behavior of ioctls such as
KVM_SET_NESTED_STATE.  We can initialize them once and for all
right after the CPU is realized, since they will never be modified
by the guest.

Reported-by: Qingua Cheng <qcheng@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1579544504-3616-2-git-send-email-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2020-01-20 19:21:42 +01:00
parent eab967935e
commit 420ae1fc51
2 changed files with 49 additions and 33 deletions
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81
target/i386/kvm.c
View File

@ -67,6 +67,8 @@
* 255 kvm_msr_entry structs */
#define MSR_BUF_SIZE 4096
static void kvm_init_msrs(X86CPU *cpu);
const KVMCapabilityInfo kvm_arch_required_capabilities[] = {
KVM_CAP_INFO(SET_TSS_ADDR),
KVM_CAP_INFO(EXT_CPUID),
@ -1842,6 +1844,8 @@ int kvm_arch_init_vcpu(CPUState *cs)
has_msr_tsc_aux = false;
}
kvm_init_msrs(cpu);
r = hyperv_init_vcpu(cpu);
if (r) {
goto fail;
@ -2660,11 +2664,53 @@ static void kvm_msr_entry_add_vmx(X86CPU *cpu, FeatureWordArray f)
VMCS12_MAX_FIELD_INDEX << 1);
}
static int kvm_buf_set_msrs(X86CPU *cpu)
{
int ret = kvm_vcpu_ioctl(CPU(cpu), KVM_SET_MSRS, cpu->kvm_msr_buf);
if (ret < 0) {
return ret;
}
if (ret < cpu->kvm_msr_buf->nmsrs) {
struct kvm_msr_entry *e = &cpu->kvm_msr_buf->entries[ret];
error_report("error: failed to set MSR 0x%" PRIx32 " to 0x%" PRIx64,
(uint32_t)e->index, (uint64_t)e->data);
}
assert(ret == cpu->kvm_msr_buf->nmsrs);
return 0;
}
static void kvm_init_msrs(X86CPU *cpu)
{
CPUX86State *env = &cpu->env;
kvm_msr_buf_reset(cpu);
if (has_msr_arch_capabs) {
kvm_msr_entry_add(cpu, MSR_IA32_ARCH_CAPABILITIES,
env->features[FEAT_ARCH_CAPABILITIES]);
}
if (has_msr_core_capabs) {
kvm_msr_entry_add(cpu, MSR_IA32_CORE_CAPABILITY,
env->features[FEAT_CORE_CAPABILITY]);
}
/*
* Older kernels do not include VMX MSRs in KVM_GET_MSR_INDEX_LIST, but
* all kernels with MSR features should have them.
*/
if (kvm_feature_msrs && cpu_has_vmx(env)) {
kvm_msr_entry_add_vmx(cpu, env->features);
}
assert(kvm_buf_set_msrs(cpu) == 0);
}
static int kvm_put_msrs(X86CPU *cpu, int level)
{
CPUX86State *env = &cpu->env;
int i;
int ret;
kvm_msr_buf_reset(cpu);
@ -2722,17 +2768,6 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
}
#endif
/* If host supports feature MSR, write down. */
if (has_msr_arch_capabs) {
kvm_msr_entry_add(cpu, MSR_IA32_ARCH_CAPABILITIES,
env->features[FEAT_ARCH_CAPABILITIES]);
}
if (has_msr_core_capabs) {
kvm_msr_entry_add(cpu, MSR_IA32_CORE_CAPABILITY,
env->features[FEAT_CORE_CAPABILITY]);
}
/*
* The following MSRs have side effects on the guest or are too heavy
* for normal writeback. Limit them to reset or full state updates.
@ -2910,14 +2945,6 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
/* Note: MSR_IA32_FEATURE_CONTROL is written separately, see
* kvm_put_msr_feature_control. */
/*
* Older kernels do not include VMX MSRs in KVM_GET_MSR_INDEX_LIST, but
* all kernels with MSR features should have them.
*/
if (kvm_feature_msrs && cpu_has_vmx(env)) {
kvm_msr_entry_add_vmx(cpu, env->features);
}
}
if (env->mcg_cap) {
@ -2933,19 +2960,7 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
}
}
ret = kvm_vcpu_ioctl(CPU(cpu), KVM_SET_MSRS, cpu->kvm_msr_buf);
if (ret < 0) {
return ret;
}
if (ret < cpu->kvm_msr_buf->nmsrs) {
struct kvm_msr_entry *e = &cpu->kvm_msr_buf->entries[ret];
error_report("error: failed to set MSR 0x%" PRIx32 " to 0x%" PRIx64,
(uint32_t)e->index, (uint64_t)e->data);
}
assert(ret == cpu->kvm_msr_buf->nmsrs);
return 0;
return kvm_buf_set_msrs(cpu);
}

1
target/i386/kvm_i386.h
View File

@ -46,4 +46,5 @@ bool kvm_enable_x2apic(void);
bool kvm_has_x2apic_api(void);
bool kvm_hv_vpindex_settable(void);
#endif