KVM: use KVM_{GET|SET}_SREGS2 when supported.

This allows to make PDPTRs part of the migration
stream and thus not reload them after migration which
is against X86 spec.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20211101132300.192584-2-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Maxim Levitsky 2021-11-01 15:22:58 +02:00 committed by Paolo Bonzini
parent b7a75c8c42
commit 8f515d3869
3 changed files with 138 additions and 2 deletions

View File

@ -1455,6 +1455,9 @@ typedef struct CPUX86State {
SegmentCache idt; /* only base and limit are used */
target_ulong cr[5]; /* NOTE: cr1 is unused */
bool pdptrs_valid;
uint64_t pdptrs[4];
int32_t a20_mask;
BNDReg bnd_regs[4];

View File

@ -124,6 +124,7 @@ static uint32_t num_architectural_pmu_fixed_counters;
static int has_xsave;
static int has_xcrs;
static int has_pit_state2;
static int has_sregs2;
static int has_exception_payload;
static bool has_msr_mcg_ext_ctl;
@ -2324,6 +2325,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
has_xsave = kvm_check_extension(s, KVM_CAP_XSAVE);
has_xcrs = kvm_check_extension(s, KVM_CAP_XCRS);
has_pit_state2 = kvm_check_extension(s, KVM_CAP_PIT_STATE2);
has_sregs2 = kvm_check_extension(s, KVM_CAP_SREGS2) > 0;
hv_vpindex_settable = kvm_check_extension(s, KVM_CAP_HYPERV_VP_INDEX);
@ -2650,6 +2652,61 @@ static int kvm_put_sregs(X86CPU *cpu)
return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_SREGS, &sregs);
}
static int kvm_put_sregs2(X86CPU *cpu)
{
CPUX86State *env = &cpu->env;
struct kvm_sregs2 sregs;
int i;
sregs.flags = 0;
if ((env->eflags & VM_MASK)) {
set_v8086_seg(&sregs.cs, &env->segs[R_CS]);
set_v8086_seg(&sregs.ds, &env->segs[R_DS]);
set_v8086_seg(&sregs.es, &env->segs[R_ES]);
set_v8086_seg(&sregs.fs, &env->segs[R_FS]);
set_v8086_seg(&sregs.gs, &env->segs[R_GS]);
set_v8086_seg(&sregs.ss, &env->segs[R_SS]);
} else {
set_seg(&sregs.cs, &env->segs[R_CS]);
set_seg(&sregs.ds, &env->segs[R_DS]);
set_seg(&sregs.es, &env->segs[R_ES]);
set_seg(&sregs.fs, &env->segs[R_FS]);
set_seg(&sregs.gs, &env->segs[R_GS]);
set_seg(&sregs.ss, &env->segs[R_SS]);
}
set_seg(&sregs.tr, &env->tr);
set_seg(&sregs.ldt, &env->ldt);
sregs.idt.limit = env->idt.limit;
sregs.idt.base = env->idt.base;
memset(sregs.idt.padding, 0, sizeof sregs.idt.padding);
sregs.gdt.limit = env->gdt.limit;
sregs.gdt.base = env->gdt.base;
memset(sregs.gdt.padding, 0, sizeof sregs.gdt.padding);
sregs.cr0 = env->cr[0];
sregs.cr2 = env->cr[2];
sregs.cr3 = env->cr[3];
sregs.cr4 = env->cr[4];
sregs.cr8 = cpu_get_apic_tpr(cpu->apic_state);
sregs.apic_base = cpu_get_apic_base(cpu->apic_state);
sregs.efer = env->efer;
if (env->pdptrs_valid) {
for (i = 0; i < 4; i++) {
sregs.pdptrs[i] = env->pdptrs[i];
}
sregs.flags |= KVM_SREGS2_FLAGS_PDPTRS_VALID;
}
return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_SREGS2, &sregs);
}
static void kvm_msr_buf_reset(X86CPU *cpu)
{
memset(cpu->kvm_msr_buf, 0, MSR_BUF_SIZE);
@ -3330,6 +3387,53 @@ static int kvm_get_sregs(X86CPU *cpu)
return 0;
}
static int kvm_get_sregs2(X86CPU *cpu)
{
CPUX86State *env = &cpu->env;
struct kvm_sregs2 sregs;
int i, ret;
ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_SREGS2, &sregs);
if (ret < 0) {
return ret;
}
get_seg(&env->segs[R_CS], &sregs.cs);
get_seg(&env->segs[R_DS], &sregs.ds);
get_seg(&env->segs[R_ES], &sregs.es);
get_seg(&env->segs[R_FS], &sregs.fs);
get_seg(&env->segs[R_GS], &sregs.gs);
get_seg(&env->segs[R_SS], &sregs.ss);
get_seg(&env->tr, &sregs.tr);
get_seg(&env->ldt, &sregs.ldt);
env->idt.limit = sregs.idt.limit;
env->idt.base = sregs.idt.base;
env->gdt.limit = sregs.gdt.limit;
env->gdt.base = sregs.gdt.base;
env->cr[0] = sregs.cr0;
env->cr[2] = sregs.cr2;
env->cr[3] = sregs.cr3;
env->cr[4] = sregs.cr4;
env->efer = sregs.efer;
env->pdptrs_valid = sregs.flags & KVM_SREGS2_FLAGS_PDPTRS_VALID;
if (env->pdptrs_valid) {
for (i = 0; i < 4; i++) {
env->pdptrs[i] = sregs.pdptrs[i];
}
}
/* changes to apic base and cr8/tpr are read back via kvm_arch_post_run */
x86_update_hflags(env);
return 0;
}
static int kvm_get_msrs(X86CPU *cpu)
{
CPUX86State *env = &cpu->env;
@ -4173,7 +4277,7 @@ int kvm_arch_put_registers(CPUState *cpu, int level)
assert(cpu_is_stopped(cpu) || qemu_cpu_is_self(cpu));
/* must be before kvm_put_nested_state so that EFER.SVME is set */
ret = kvm_put_sregs(x86_cpu);
ret = has_sregs2 ? kvm_put_sregs2(x86_cpu) : kvm_put_sregs(x86_cpu);
if (ret < 0) {
return ret;
}
@ -4278,7 +4382,7 @@ int kvm_arch_get_registers(CPUState *cs)
if (ret < 0) {
goto out;
}
ret = kvm_get_sregs(cpu);
ret = has_sregs2 ? kvm_get_sregs2(cpu) : kvm_get_sregs(cpu);
if (ret < 0) {
goto out;
}

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@ -1451,6 +1451,34 @@ static const VMStateDescription vmstate_msr_intel_sgx = {
.needed = intel_sgx_msrs_needed,
.fields = (VMStateField[]) {
VMSTATE_UINT64_ARRAY(env.msr_ia32_sgxlepubkeyhash, X86CPU, 4),
VMSTATE_END_OF_LIST()
}
};
static bool pdptrs_needed(void *opaque)
{
X86CPU *cpu = opaque;
CPUX86State *env = &cpu->env;
return env->pdptrs_valid;
}
static int pdptrs_post_load(void *opaque, int version_id)
{
X86CPU *cpu = opaque;
CPUX86State *env = &cpu->env;
env->pdptrs_valid = true;
return 0;
}
static const VMStateDescription vmstate_pdptrs = {
.name = "cpu/pdptrs",
.version_id = 1,
.minimum_version_id = 1,
.needed = pdptrs_needed,
.post_load = pdptrs_post_load,
.fields = (VMStateField[]) {
VMSTATE_UINT64_ARRAY(env.pdptrs, X86CPU, 4),
VMSTATE_END_OF_LIST()
}
};
@ -1593,6 +1621,7 @@ const VMStateDescription vmstate_x86_cpu = {
#endif
&vmstate_msr_tsx_ctrl,
&vmstate_msr_intel_sgx,
&vmstate_pdptrs,
NULL
}
};