Re: [Qemu-devel] [PATCH v3 2/2] target/i386: Add support for save/load IA32_UMWAIT_CONTROL MSR

[Tao Xu]

On 6/17/2019 11:39 AM, Xiaoyao Li wrote:
> On 6/16/2019 11:35 PM, Tao Xu wrote:
> > UMWAIT and TPAUSE instructions use IA32_UMWAIT_CONTROL at MSR index
> > E1H to determines the maximum time in TSC-quanta that the processor
> > can reside in either C0.1 or C0.2.
> >
> > This patch is to Add support for save/load IA32_UMWAIT_CONTROL MSR in
> > guest.
> >
> > Co-developed-by: Jingqi Liu <address@hidden>
> > Signed-off-by: Jingqi Liu <address@hidden>
> > Signed-off-by: Tao Xu <address@hidden>
> > ---
> >
> > no changes in v3:
> > ---
> >   target/i386/cpu.h     |  2 ++
> >   target/i386/kvm.c     | 13 +++++++++++++
> >   target/i386/machine.c | 20 ++++++++++++++++++++
> >   3 files changed, 35 insertions(+)
> >
> > diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> > index 2f7c57a3c2..eb98b2e54a 100644
> > --- a/target/i386/cpu.h
> > +++ b/target/i386/cpu.h
> > @@ -450,6 +450,7 @@ typedef enum X86Seg {
> >   #define MSR_IA32_BNDCFGS                0x00000d90
> >   #define MSR_IA32_XSS                    0x00000da0
> > +#define MSR_IA32_UMWAIT_CONTROL         0xe1
> >   #define XSTATE_FP_BIT                   0
> >   #define XSTATE_SSE_BIT                  1
> > @@ -1348,6 +1349,7 @@ typedef struct CPUX86State {
> >       uint16_t fpregs_format_vmstate;
> >       uint64_t xss;
> > +    uint64_t umwait;
> >       TPRAccess tpr_access_type;
> >   } CPUX86State;
> > diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> > index 3efdb90f11..506c7cd038 100644
> > --- a/target/i386/kvm.c
> > +++ b/target/i386/kvm.c
> > @@ -91,6 +91,7 @@ static bool has_msr_hv_stimer;
> >   static bool has_msr_hv_frequencies;
> >   static bool has_msr_hv_reenlightenment;
> >   static bool has_msr_xss;
> > +static bool has_msr_umwait;
> >   static bool has_msr_spec_ctrl;
> >   static bool has_msr_virt_ssbd;
> >   static bool has_msr_smi_count;
> > @@ -1486,6 +1487,9 @@ static int kvm_get_supported_msrs(KVMState *s)
> >                   case MSR_IA32_XSS:
> >                       has_msr_xss = true;
> >                       break;
> > +                case MSR_IA32_UMWAIT_CONTROL:
> > +                    has_msr_umwait = true;
> > +                    break;
>
> Need to add MSR_IA32_UMWAIT_CONTROL into msrs_to_save[] in your kvm 
> patches, otherwise qemu never goes into this case.
OK, thank you for your suggestion. I will add it in the next version.