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i386: prefer system KVM_GET_SUPPORTED_HV_CPUID ioctl over vCPU's one

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KVM_GET_SUPPORTED_HV_CPUID was made a system wide ioctl which can be called
prior to creating vCPUs and we are going to use that to expand Hyper-V cpu
features early. Use it when it is supported by KVM.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20210422161130.652779-14-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
This commit is contained in:
Vitaly Kuznetsov 2021-04-22 18:11:24 +02:00 committed by Eduardo Habkost
parent 05c900ce73
commit 2e905438cf
1 changed files with 13 additions and 4 deletions
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17
target/i386/kvm/kvm.c
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@ -929,7 +929,8 @@ static struct {
},
};
static struct kvm_cpuid2 *try_get_hv_cpuid(CPUState *cs, int max)
static struct kvm_cpuid2 *try_get_hv_cpuid(CPUState *cs, int max,
bool do_sys_ioctl)
{
struct kvm_cpuid2 *cpuid;
int r, size;
@ -938,7 +939,11 @@ static struct kvm_cpuid2 *try_get_hv_cpuid(CPUState *cs, int max)
cpuid = g_malloc0(size);
cpuid->nent = max;
r = kvm_vcpu_ioctl(cs, KVM_GET_SUPPORTED_HV_CPUID, cpuid);
if (do_sys_ioctl) {
r = kvm_ioctl(kvm_state, KVM_GET_SUPPORTED_HV_CPUID, cpuid);
} else {
r = kvm_vcpu_ioctl(cs, KVM_GET_SUPPORTED_HV_CPUID, cpuid);
}
if (r == 0 && cpuid->nent >= max) {
r = -E2BIG;
}
@ -965,13 +970,17 @@ static struct kvm_cpuid2 *get_supported_hv_cpuid(CPUState *cs)
/* 0x40000000..0x40000005, 0x4000000A, 0x40000080..0x40000080 leaves */
int max = 10;
int i;
bool do_sys_ioctl;
do_sys_ioctl =
kvm_check_extension(kvm_state, KVM_CAP_SYS_HYPERV_CPUID) > 0;
/*
* When the buffer is too small, KVM_GET_SUPPORTED_HV_CPUID fails with
* -E2BIG, however, it doesn't report back the right size. Keep increasing
* it and re-trying until we succeed.
*/
while ((cpuid = try_get_hv_cpuid(cs, max)) == NULL) {
while ((cpuid = try_get_hv_cpuid(cs, max, do_sys_ioctl)) == NULL) {
max++;
}
@ -981,7 +990,7 @@ static struct kvm_cpuid2 *get_supported_hv_cpuid(CPUState *cs)
* information early, just check for the capability and set the bit
* manually.
*/
if (kvm_check_extension(cs->kvm_state,
if (!do_sys_ioctl && kvm_check_extension(cs->kvm_state,
KVM_CAP_HYPERV_ENLIGHTENED_VMCS) > 0) {
for (i = 0; i < cpuid->nent; i++) {
if (cpuid->entries[i].function == HV_CPUID_ENLIGHTMENT_INFO) {