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kvm: x86: Avoid runtime allocation of xsave buffer 

Keep a per-VCPU xsave buffer for kvm_put/get_xsave instead of
continuously allocating and freeing it on state sync.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Jan Kiszka 2011-10-27 19:25:58 +02:00 committed by Marcelo Tosatti
parent 6b42494b21
commit fabacc0f79
2 changed files with 9 additions and 9 deletions
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3
target-i386/cpu.h
View File

@ -751,7 +751,8 @@ typedef struct CPUX86State {
uint32_t cpuid_svm_features;
bool tsc_valid;
int tsc_khz;
void *kvm_xsave_buf;
/* in order to simplify APIC support, we leave this pointer to the
user */
struct DeviceState *apic_state;

15
target-i386/kvm.c
View File

@ -516,6 +516,10 @@ int kvm_arch_init_vcpu(CPUState *env)
}
}
if (kvm_has_xsave()) {
env->kvm_xsave_buf = qemu_memalign(4096, sizeof(struct kvm_xsave));
}
return 0;
}
@ -771,15 +775,14 @@ static int kvm_put_fpu(CPUState *env)
static int kvm_put_xsave(CPUState *env)
{
int i, r;
struct kvm_xsave* xsave;
struct kvm_xsave* xsave = env->kvm_xsave_buf;
uint16_t cwd, swd, twd;
int i, r;
if (!kvm_has_xsave()) {
return kvm_put_fpu(env);
}
xsave = qemu_memalign(4096, sizeof(struct kvm_xsave));
memset(xsave, 0, sizeof(struct kvm_xsave));
twd = 0;
swd = env->fpus & ~(7 << 11);
@ -801,7 +804,6 @@ static int kvm_put_xsave(CPUState *env)
memcpy(&xsave->region[XSAVE_YMMH_SPACE], env->ymmh_regs,
sizeof env->ymmh_regs);
r = kvm_vcpu_ioctl(env, KVM_SET_XSAVE, xsave);
g_free(xsave);
return r;
}
@ -978,7 +980,7 @@ static int kvm_get_fpu(CPUState *env)
static int kvm_get_xsave(CPUState *env)
{
struct kvm_xsave* xsave;
struct kvm_xsave* xsave = env->kvm_xsave_buf;
int ret, i;
uint16_t cwd, swd, twd;
@ -986,10 +988,8 @@ static int kvm_get_xsave(CPUState *env)
return kvm_get_fpu(env);
}
xsave = qemu_memalign(4096, sizeof(struct kvm_xsave));
ret = kvm_vcpu_ioctl(env, KVM_GET_XSAVE, xsave);
if (ret < 0) {
g_free(xsave);
return ret;
}
@ -1013,7 +1013,6 @@ static int kvm_get_xsave(CPUState *env)
env->xstate_bv = *(uint64_t *)&xsave->region[XSAVE_XSTATE_BV];
memcpy(env->ymmh_regs, &xsave->region[XSAVE_YMMH_SPACE],
sizeof env->ymmh_regs);
g_free(xsave);
return 0;
}