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[Qemu-devel] [RFC untested PATCH] i386/cpu: make -cpu host support monit
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] [RFC untested PATCH] i386/cpu: make -cpu host support monitor/mwait |
Date: |
Fri, 8 Jun 2018 23:59:19 +0300 |
When guest CPU PM is enabled, and with -cpu host, expose the host CPU
MWAIT leaf to guest so guest can make good PM decisions.
Signed-off-by: Michael S. Tsirkin <address@hidden>
---
This builds but is untested. Is this a reasonable way to go about it?
target/i386/cpu.h | 9 +++++++++
target/i386/cpu.c | 18 +++++++++++++-----
2 files changed, 22 insertions(+), 5 deletions(-)
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 664504610e..309f804573 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -1378,6 +1378,15 @@ struct X86CPU {
/* if true the CPUID code directly forward host cache leaves to the guest
*/
bool cache_info_passthrough;
+ /* if true the CPUID code directly forwards
+ * host monitor/mwait leaves to the guest */
+ struct {
+ uint32_t eax;
+ uint32_t ebx;
+ uint32_t ecx;
+ uint32_t edx;
+ } mwait;
+
/* Features that were filtered out because of missing host capabilities */
uint32_t filtered_features[FEATURE_WORDS];
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 94260412e2..a49443de56 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -3760,11 +3760,11 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
uint32_t count,
}
break;
case 5:
- /* mwait info: needed for Core compatibility */
- *eax = 0; /* Smallest monitor-line size in bytes */
- *ebx = 0; /* Largest monitor-line size in bytes */
- *ecx = CPUID_MWAIT_EMX | CPUID_MWAIT_IBE;
- *edx = 0;
+ /* MONITOR/MWAIT Leaf */
+ *eax = cpu->mwait.eax; /* Smallest monitor-line size in bytes */
+ *ebx = cpu->mwait.ebx; /* Largest monitor-line size in bytes */
+ *ecx = cpu->mwait.ecx; /* flags */
+ *edx = cpu->mwait.edx; /* mwait substates */
break;
case 6:
/* Thermal and Power Leaf */
@@ -4595,6 +4595,14 @@ static void x86_cpu_realizefn(DeviceState *dev, Error
**errp)
goto out;
}
+ if (xcc->host_cpuid_required && enable_cpu_pm) {
+ host_cpuid(5, 0, &cpu->mwait.eax, &cpu->mwait.ebx,
+ &cpu->mwait.ecx, &cpu->mwait.edx);
+ }
+ /* We always wake on interrupt even if host does not have the capability */
+ /* mwait extended info: needed for Core compatibility */
+ cpu->mwait.ecx |= CPUID_MWAIT_EMX | CPUID_MWAIT_IBE;
+
if (cpu->apic_id == UNASSIGNED_APIC_ID) {
error_setg(errp, "apic-id property was not initialized properly");
return;
--
MST
- [Qemu-devel] [RFC untested PATCH] i386/cpu: make -cpu host support monitor/mwait,
Michael S. Tsirkin <=
- Re: [Qemu-devel] [RFC untested PATCH] i386/cpu: make -cpu host support monitor/mwait, no-reply, 2018/06/08
- Re: [Qemu-devel] [RFC untested PATCH] i386/cpu: make -cpu host support monitor/mwait, no-reply, 2018/06/08
- Re: [Qemu-devel] [RFC untested PATCH] i386/cpu: make -cpu host support monitor/mwait, Eduardo Habkost, 2018/06/11
- Re: [Qemu-devel] [RFC untested PATCH] i386/cpu: make -cpu host support monitor/mwait, Igor Mammedov, 2018/06/12
- Re: [Qemu-devel] [RFC untested PATCH] i386/cpu: make -cpu host support monitor/mwait, Michael S. Tsirkin, 2018/06/12
- Re: [Qemu-devel] [RFC untested PATCH] i386/cpu: make -cpu host support monitor/mwait, Igor Mammedov, 2018/06/12
- Re: [Qemu-devel] [RFC untested PATCH] i386/cpu: make -cpu host support monitor/mwait, Eduardo Habkost, 2018/06/12
- Re: [Qemu-devel] [RFC untested PATCH] i386/cpu: make -cpu host support monitor/mwait, Igor Mammedov, 2018/06/13
- Re: [Qemu-devel] [RFC untested PATCH] i386/cpu: make -cpu host support monitor/mwait, Michael S. Tsirkin, 2018/06/13
- Re: [Qemu-devel] [RFC untested PATCH] i386/cpu: make -cpu host support monitor/mwait, Eduardo Habkost, 2018/06/13