On Sun, 2010-01-17 at 14:20 +0200, Avi Kivity wrote:
> On 01/17/2010 11:03 AM, Gleb Natapov wrote:
>
> > Signed-off-by: Gleb Natapov<gleb@xxxxxxxxxx>
> > Signed-off-by: Vadim Rozenfeld<vrozenfe@xxxxxxxxxx>
> >
>
> Changelog entry.
>
> >
> > struct kvm_mem_alias {
> > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> > index ba8c045..4b224f9 100644
> > --- a/arch/x86/kvm/lapic.c
> > +++ b/arch/x86/kvm/lapic.c
> > @@ -1246,3 +1246,34 @@ int kvm_x2apic_msr_read(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
> >
> > return 0;
> > }
> > +
> > +int kvm_hv_vapic_msr_write(struct kvm_vcpu *vcpu, u32 reg, u64 data)
> > +{
> > + struct kvm_lapic *apic = vcpu->arch.apic;
> > +
> > + if (!irqchip_in_kernel(vcpu->kvm))
> > + return 1;
> > +
> > + /* if this is ICR write vector before command */
> > + if (reg == APIC_ICR)
> > + apic_reg_write(apic, APIC_ICR2, (u32)(data>> 32));
> > + return apic_reg_write(apic, reg, (u32)data);
> > +}
> > +
> > +int kvm_hv_vapic_msr_read(struct kvm_vcpu *vcpu, u32 reg, u64 *data)
> > +{
> > + struct kvm_lapic *apic = vcpu->arch.apic;
> > + u32 low, high = 0;
> > +
> > + if (!irqchip_in_kernel(vcpu->kvm))
> > + return 1;
> > +
> > + if (apic_reg_read(apic, reg, 4,&low))
> > + return 1;
> > + if (reg == APIC_ICR)
> > + apic_reg_read(apic, APIC_ICR2, 4,&high);
> > +
> > + *data = (((u64)high)<< 32) | low;
> > +
> > + return 0;
> > +}
> >
>
> I prefer putting this in x86.c (maybe later split into hyperv.c).
>
> > diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
> > index 40010b0..d081cb6 100644
> > --- a/arch/x86/kvm/lapic.h
> > +++ b/arch/x86/kvm/lapic.h
> > @@ -48,4 +48,12 @@ void kvm_lapic_sync_to_vapic(struct kvm_vcpu *vcpu);
> >
> > int kvm_x2apic_msr_write(struct kvm_vcpu *vcpu, u32 msr, u64 data);
> > int kvm_x2apic_msr_read(struct kvm_vcpu *vcpu, u32 msr, u64 *data);
> > +
> > +int kvm_hv_vapic_msr_write(struct kvm_vcpu *vcpu, u32 msr, u64 data);
> > +int kvm_hv_vapic_msr_read(struct kvm_vcpu *vcpu, u32 msr, u64 *data);
> > +
> > +static inline bool kvm_hv_vapic_enabled(struct kvm_vcpu *vcpu)
> > +{
> > + return !!(vcpu->arch.hv_vapic& HV_X64_MSR_APIC_ASSIST_PAGE_ENABLE);
> > +}
> >
>
> Are you sure that vapic enabled is equivalent to apic assist page enable?
At least, when it is disable, the EOI interception mechanism won't
work.
>
> !! not required.
>
> > #endif
> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > index db0b2b1..2fe555c 100644
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> > @@ -632,6 +632,7 @@ static u32 msrs_to_save[] = {
> > #endif
> > MSR_IA32_TSC, MSR_IA32_PERF_STATUS, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA,
> > HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL,
> > + HV_X64_MSR_APIC_ASSIST_PAGE,
> > };
> >
> >
>
> Will be dropped by msr validation.
>
> > static unsigned num_msrs_to_save;
> > @@ -1063,10 +1064,37 @@ static int set_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data)
> >
> > static int set_msr_hyperv(struct kvm_vcpu *vcpu, u32 msr, u64 data)
> > {
> > - pr_unimpl(vcpu, "HYPER-V unimplemented wrmsr: 0x%x data 0x%llx\n",
> > - msr, data);
> > + switch (msr) {
> > + case HV_X64_MSR_APIC_ASSIST_PAGE: {
> > + unsigned long vaddr;
> > + void *addr;
> > + struct page *page;
> > + vcpu->arch.hv_vapic = data;
> > + if (!kvm_hv_vapic_enabled(vcpu))
> > + break;
> > + vaddr = gfn_to_hva(vcpu->kvm, data>>
> > + HV_X64_MSR_APIC_ASSIST_PAGE_ADDRESS_SHIFT);
> > + if (kvm_is_error_hva(vaddr))
> > + return 1;
> > + page = virt_to_page(vaddr);
> >
>
> virt_to_page() takes a kernel address, not a user address. This is
> get_user_pages(). But I think the whole thing is done better with
> put_user().
>
> > + addr = kmap_atomic(page, KM_USER0);
> > + clear_user_page(addr, vaddr, page);
> > + kunmap_atomic(addr, KM_USER0);
> >
>
> Surprising that clear_user_page needs kmap_atomic() (but true).
>
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