On Sun, Jan 17, 2010 at 02:20:32PM +0200, Avi Kivity wrote:
> On 01/17/2010 11:03 AM, Gleb Natapov wrote:
> 
> >Signed-off-by: Gleb Natapov<[email protected]>
> >Signed-off-by: Vadim Rozenfeld<[email protected]>
> 
> 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).
> 
This implements part of apic behaviour. It uses internal lapic functions
like apic_reg_read()/apic_reg_write(). Why move it from lapic.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?
> 
> !! not required.
> 
The function is not used to check if vapic is enabled, so the name
should be changed.

> >  #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().
> 
So there is no function to get struct page from user virtual address?

> >+            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).
> 
> -- 
> error compiling committee.c: too many arguments to function

--
                        Gleb.
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