Il 16/09/2014 12:42, Tang Chen ha scritto:
> This patch only handle "L1 and L2 vm share one apic access page" situation.
>
> When L1 vm is running, if the shared apic access page is migrated, mmu_notifier will
> request all vcpus to exit to L0, and reload apic access page physical address for
> all the vcpus' vmcs (which is done by patch 5/6). And when it enters L2 vm, L2's vmcs
> will be updated in prepare_vmcs02() called by nested_vm_run(). So we need to do
> nothing.
>
> When L2 vm is running, if the shared apic access page is migrated, mmu_notifier will
> request all vcpus to exit to L0, and reload apic access page physical address for
> all L2 vmcs. And this patch requests apic access page reload in L2->L1 vmexit.
>
> Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
But if kvm_vcpu_reload_apic_access_page is called when the active VMCS
is a VMCS02, the APIC access address will be corrupted, no?
So, even if you are not touching the pages pinned by nested virt, you
need an
if (!is_guest_mode(vcpu) ||
!(vmx->nested.current_vmcs12->secondary_vm_exec_control &
SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES))
as suggested by Gleb in the review of v5.
Paolo
> ---
> arch/x86/include/asm/kvm_host.h | 1 +
> arch/x86/kvm/vmx.c | 6 ++++++
> arch/x86/kvm/x86.c | 3 ++-
> 3 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 514183e..92b3e72 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1046,6 +1046,7 @@ int kvm_cpu_has_interrupt(struct kvm_vcpu *vcpu);
> int kvm_arch_interrupt_allowed(struct kvm_vcpu *vcpu);
> int kvm_cpu_get_interrupt(struct kvm_vcpu *v);
> void kvm_vcpu_reset(struct kvm_vcpu *vcpu);
> +void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu);
>
> void kvm_define_shared_msr(unsigned index, u32 msr);
> void kvm_set_shared_msr(unsigned index, u64 val, u64 mask);
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index a1a9797..d0d5981 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -8795,6 +8795,12 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
> }
>
> /*
> + * We are now running in L2, mmu_notifier will force to reload the
> + * page's hpa for L2 vmcs. Need to reload it for L1 before entering L1.
> + */
> + kvm_vcpu_reload_apic_access_page(vcpu);
> +
> + /*
> * Exiting from L2 to L1, we're now back to L1 which thinks it just
> * finished a VMLAUNCH or VMRESUME instruction, so we need to set the
> * success or failure flag accordingly.
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 27c3d30..3f458b2 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -5989,7 +5989,7 @@ static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu)
> kvm_apic_update_tmr(vcpu, tmr);
> }
>
> -static void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu)
> +void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu)
> {
> /*
> * apic access page could be migrated. When the page is being migrated,
> @@ -6001,6 +6001,7 @@ static void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu)
> kvm_x86_ops->set_apic_access_page_addr(vcpu->kvm,
> page_to_phys(vcpu->kvm->arch.apic_access_page));
> }
> +EXPORT_SYMBOL_GPL(kvm_vcpu_reload_apic_access_page);
>
> /*
> * Returns 1 to let __vcpu_run() continue the guest execution loop without
>
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