target/i386/kvm/kvm.c | 48 ++++++++++++++++++++++++------------------- 1 file changed, 27 insertions(+), 21 deletions(-)
When try to get one msr from KVM, I found there's no such kind of
existing interface while kvm_put_one_msr() is there. So here comes
the patch. It'll remove redundant preparation code before finally
call KVM_GET_MSRS IOCTL.
No functional change intended.
Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
---
target/i386/kvm/kvm.c | 48 ++++++++++++++++++++++++-------------------
1 file changed, 27 insertions(+), 21 deletions(-)
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 2c8feb4a6f..c897dbaf60 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -135,6 +135,7 @@ static struct kvm_msr_list *kvm_feature_msrs;
#define BUS_LOCK_SLICE_TIME 1000000000ULL /* ns */
static RateLimit bus_lock_ratelimit_ctrl;
+static int kvm_get_one_msr(X86CPU *cpu, int index, uint64_t *value);
int kvm_has_pit_state2(void)
{
@@ -205,28 +206,21 @@ static int kvm_get_tsc(CPUState *cs)
{
X86CPU *cpu = X86_CPU(cs);
CPUX86State *env = &cpu->env;
- struct {
- struct kvm_msrs info;
- struct kvm_msr_entry entries[1];
- } msr_data = {};
+ uint64_t value;
int ret;
if (env->tsc_valid) {
return 0;
}
- memset(&msr_data, 0, sizeof(msr_data));
- msr_data.info.nmsrs = 1;
- msr_data.entries[0].index = MSR_IA32_TSC;
env->tsc_valid = !runstate_is_running();
- ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MSRS, &msr_data);
+ ret = kvm_get_one_msr(cpu, MSR_IA32_TSC, &value);
if (ret < 0) {
return ret;
}
- assert(ret == 1);
- env->tsc = msr_data.entries[0].data;
+ env->tsc = value;
return 0;
}
@@ -1478,21 +1472,14 @@ static int hyperv_init_vcpu(X86CPU *cpu)
* the kernel doesn't support setting vp_index; assert that its value
* is in sync
*/
- struct {
- struct kvm_msrs info;
- struct kvm_msr_entry entries[1];
- } msr_data = {
- .info.nmsrs = 1,
- .entries[0].index = HV_X64_MSR_VP_INDEX,
- };
-
- ret = kvm_vcpu_ioctl(cs, KVM_GET_MSRS, &msr_data);
+ uint64_t value;
+
+ ret = kvm_get_one_msr(cpu, HV_X64_MSR_VP_INDEX, &value);
if (ret < 0) {
return ret;
}
- assert(ret == 1);
- if (msr_data.entries[0].data != hyperv_vp_index(CPU(cpu))) {
+ if (value != hyperv_vp_index(CPU(cpu))) {
error_report("kernel's vp_index != QEMU's vp_index");
return -ENXIO;
}
@@ -2734,6 +2721,25 @@ static int kvm_put_one_msr(X86CPU *cpu, int index, uint64_t value)
return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_MSRS, cpu->kvm_msr_buf);
}
+static int kvm_get_one_msr(X86CPU *cpu, int index, uint64_t *value)
+{
+ int ret;
+ struct {
+ struct kvm_msrs info;
+ struct kvm_msr_entry entries[1];
+ } msr_data = {
+ .info.nmsrs = 1,
+ .entries[0].index = index,
+ };
+
+ ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MSRS, &msr_data);
+ if (ret < 0) {
+ return ret;
+ }
+ assert(ret == 1);
+ *value = msr_data.entries[0].data;
+ return ret;
+}
void kvm_put_apicbase(X86CPU *cpu, uint64_t value)
{
int ret;
--
2.27.0
On 1/27/22 16:58, Yang Weijiang wrote: > @@ -135,6 +135,7 @@ static struct kvm_msr_list *kvm_feature_msrs; > > #define BUS_LOCK_SLICE_TIME 1000000000ULL /* ns */ > static RateLimit bus_lock_ratelimit_ctrl; > +static int kvm_get_one_msr(X86CPU *cpu, int index, uint64_t *value); > > int kvm_has_pit_state2(void) > { ... > @@ -2734,6 +2721,25 @@ static int kvm_put_one_msr(X86CPU *cpu, int index, uint64_t value) > return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_MSRS, cpu->kvm_msr_buf); > } > > +static int kvm_get_one_msr(X86CPU *cpu, int index, uint64_t *value) > +{ > + int ret; > + struct { > + struct kvm_msrs info; > + struct kvm_msr_entry entries[1]; > + } msr_data = { > + .info.nmsrs = 1, > + .entries[0].index = index, > + }; > + > + ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MSRS, &msr_data); > + if (ret < 0) { > + return ret; > + } > + assert(ret == 1); > + *value = msr_data.entries[0].data; > + return ret; > +} > void kvm_put_apicbase(X86CPU *cpu, uint64_t value) > { > int ret; The patch is a good idea, but you can put the function before the uses. This way there will be no need for a forward declaration, either. Thanks, Paolo
On 1/28/2022 6:55 PM, Paolo Bonzini wrote: > On 1/27/22 16:58, Yang Weijiang wrote: >> @@ -135,6 +135,7 @@ static struct kvm_msr_list *kvm_feature_msrs; >> #define BUS_LOCK_SLICE_TIME 1000000000ULL /* ns */ >> static RateLimit bus_lock_ratelimit_ctrl; >> +static int kvm_get_one_msr(X86CPU *cpu, int index, uint64_t *value); >> int kvm_has_pit_state2(void) >> { > > ... > >> @@ -2734,6 +2721,25 @@ static int kvm_put_one_msr(X86CPU *cpu, int >> index, uint64_t value) >> return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_MSRS, cpu->kvm_msr_buf); >> } >> +static int kvm_get_one_msr(X86CPU *cpu, int index, uint64_t *value) >> +{ >> + int ret; >> + struct { >> + struct kvm_msrs info; >> + struct kvm_msr_entry entries[1]; >> + } msr_data = { >> + .info.nmsrs = 1, >> + .entries[0].index = index, >> + }; >> + >> + ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MSRS, &msr_data); >> + if (ret < 0) { >> + return ret; >> + } >> + assert(ret == 1); >> + *value = msr_data.entries[0].data; >> + return ret; >> +} >> void kvm_put_apicbase(X86CPU *cpu, uint64_t value) >> { >> int ret; > > The patch is a good idea, but you can put the function before the > uses. This way there will be no need for a forward declaration, either. Thanks Paolo! Is v2 version required for this? > > Thanks, > > Paolo
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