On 21/02/2018 18:47, KarimAllah Ahmed wrote:
> ... since using kvm_vcpu_gpa_to_page() and kmap() will only work for guest
> memory that has a "struct page".
> 
> The life-cycle of the mapping also changes to avoid doing map and unmap on
> every single exit (which becomes very expesive once we use memremap).  Now
> the memory is mapped and only unmapped when a new VMCS12 is loaded into the
> vCPU (or when the vCPU is freed!).
> 
> Signed-off-by: KarimAllah Ahmed <karah...@amazon.de>

Same here, let's change the lifecycle separately.

Paolo

> ---
>  arch/x86/kvm/vmx.c | 45 +++++++++++++--------------------------------
>  1 file changed, 13 insertions(+), 32 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index a700338..7b29419 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -461,7 +461,7 @@ struct nested_vmx {
>        */
>       struct page *apic_access_page;
>       struct kvm_host_map virtual_apic_map;
> -     struct page *pi_desc_page;
> +     struct kvm_host_map pi_desc_map;
>       struct kvm_host_map msr_bitmap_map;
>  
>       struct pi_desc *pi_desc;
> @@ -7666,6 +7666,7 @@ static inline void nested_release_vmcs12(struct 
> vcpu_vmx *vmx)
>                                 vmx->nested.cached_vmcs12, 0, VMCS12_SIZE);
>  
>       kvm_vcpu_unmap(&vmx->nested.virtual_apic_map);
> +     kvm_vcpu_unmap(&vmx->nested.pi_desc_map);
>       kvm_vcpu_unmap(&vmx->nested.msr_bitmap_map);
>  
>       vmx->nested.current_vmptr = -1ull;
> @@ -7698,14 +7699,9 @@ static void free_nested(struct vcpu_vmx *vmx)
>               vmx->nested.apic_access_page = NULL;
>       }
>       kvm_vcpu_unmap(&vmx->nested.virtual_apic_map);
> -     if (vmx->nested.pi_desc_page) {
> -             kunmap(vmx->nested.pi_desc_page);
> -             kvm_release_page_dirty(vmx->nested.pi_desc_page);
> -             vmx->nested.pi_desc_page = NULL;
> -             vmx->nested.pi_desc = NULL;
> -     }
> -
> +     kvm_vcpu_unmap(&vmx->nested.pi_desc_map);
>       kvm_vcpu_unmap(&vmx->nested.msr_bitmap_map);
> +     vmx->nested.pi_desc = NULL;
>  
>       free_loaded_vmcs(&vmx->nested.vmcs02);
>  }
> @@ -10278,24 +10274,16 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu 
> *vcpu,
>       }
>  
>       if (nested_cpu_has_posted_intr(vmcs12)) {
> -             if (vmx->nested.pi_desc_page) { /* shouldn't happen */
> -                     kunmap(vmx->nested.pi_desc_page);
> -                     kvm_release_page_dirty(vmx->nested.pi_desc_page);
> -                     vmx->nested.pi_desc_page = NULL;
> +             map = &vmx->nested.pi_desc_map;
> +
> +             if (kvm_vcpu_map(vcpu, 
> gpa_to_gfn(vmcs12->posted_intr_desc_addr), map)) {
> +                     vmx->nested.pi_desc =
> +                             (struct pi_desc *)(((void *)map->kaddr) +
> +                             offset_in_page(vmcs12->posted_intr_desc_addr));
> +                     vmcs_write64(POSTED_INTR_DESC_ADDR, 
> pfn_to_hpa(map->pfn) +
> +                                                         
> offset_in_page(vmcs12->posted_intr_desc_addr));
>               }
> -             page = kvm_vcpu_gpa_to_page(vcpu, 
> vmcs12->posted_intr_desc_addr);
> -             if (is_error_page(page))
> -                     return;
> -             vmx->nested.pi_desc_page = page;
> -             vmx->nested.pi_desc = kmap(vmx->nested.pi_desc_page);
> -             vmx->nested.pi_desc =
> -                     (struct pi_desc *)((void *)vmx->nested.pi_desc +
> -                     (unsigned long)(vmcs12->posted_intr_desc_addr &
> -                     (PAGE_SIZE - 1)));
> -             vmcs_write64(POSTED_INTR_DESC_ADDR,
> -                     page_to_phys(vmx->nested.pi_desc_page) +
> -                     (unsigned long)(vmcs12->posted_intr_desc_addr &
> -                     (PAGE_SIZE - 1)));
> +
>       }
>       if (nested_vmx_prepare_msr_bitmap(vcpu, vmcs12))
>               vmcs_set_bits(CPU_BASED_VM_EXEC_CONTROL,
> @@ -11893,13 +11881,6 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, 
> u32 exit_reason,
>               kvm_release_page_dirty(vmx->nested.apic_access_page);
>               vmx->nested.apic_access_page = NULL;
>       }
> -     if (vmx->nested.pi_desc_page) {
> -             kunmap(vmx->nested.pi_desc_page);
> -             kvm_release_page_dirty(vmx->nested.pi_desc_page);
> -             vmx->nested.pi_desc_page = NULL;
> -             vmx->nested.pi_desc = NULL;
> -     }
> -
>       /*
>        * 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.
> 

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