On Fri, Dec 09, 2022 at 12:45:51PM +0800, Robert Hoo wrote:
> The get_cr3() is the implementation of kvm_mmu::get_guest_pgd(), well, CR3
> cannot be naturally equivalent to pgd, SDM says CR3 high bits are reserved,
> must be zero.
> And now, with LAM feature's introduction, bit 61 ~ 62 are used.
> So, rename get_cr3() --> get_pgd() to better indicate function purpose and
> in it, filtered out CR3 high bits.
>
> Signed-off-by: Robert Hoo <robert.hu@xxxxxxxxxxxxxxx>
> Reviewed-by: Jingqi Liu <jingqi.liu@xxxxxxxxx>
> ---
> arch/x86/include/asm/processor-flags.h | 1 +
> arch/x86/kvm/mmu/mmu.c | 12 ++++++++----
> 2 files changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/include/asm/processor-flags.h b/arch/x86/include/asm/processor-flags.h
> index d8cccadc83a6..bb0f8dd16956 100644
> --- a/arch/x86/include/asm/processor-flags.h
> +++ b/arch/x86/include/asm/processor-flags.h
> @@ -38,6 +38,7 @@
> #ifdef CONFIG_X86_64
> /* Mask off the address space ID and SME encryption bits. */
> #define CR3_ADDR_MASK __sme_clr(PHYSICAL_PAGE_MASK)
> +#define CR3_HIGH_RSVD_MASK GENMASK_ULL(63, 52)
> #define CR3_PCID_MASK 0xFFFull
> #define CR3_NOFLUSH BIT_ULL(63)
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index b6f96d47e596..d433c8923b18 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -4488,9 +4488,13 @@ void kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd)
> }
> EXPORT_SYMBOL_GPL(kvm_mmu_new_pgd);
>
> -static unsigned long get_cr3(struct kvm_vcpu *vcpu)
> +static unsigned long get_pgd(struct kvm_vcpu *vcpu)
> {
> +#ifdef CONFIG_X86_64
> + return kvm_read_cr3(vcpu) & ~CR3_HIGH_RSVD_MASK;
CR3_HIGH_RSVD_MASK is used to extract the guest pgd, may
need to use guest's MAXPHYADDR but not hard code to 52.
Or easily, just mask out the LAM bits.
> +#else
> return kvm_read_cr3(vcpu);
> +#endif
> }
>
> static bool sync_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, gfn_t gfn,
> @@ -5043,7 +5047,7 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu,
> context->page_fault = kvm_tdp_page_fault;
> context->sync_page = nonpaging_sync_page;
> context->invlpg = NULL;
> - context->get_guest_pgd = get_cr3;
> + context->get_guest_pgd = get_pgd;
> context->get_pdptr = kvm_pdptr_read;
> context->inject_page_fault = kvm_inject_page_fault;
>
> @@ -5193,7 +5197,7 @@ static void init_kvm_softmmu(struct kvm_vcpu *vcpu,
>
> kvm_init_shadow_mmu(vcpu, cpu_role);
>
> - context->get_guest_pgd = get_cr3;
> + context->get_guest_pgd = get_pgd;
> context->get_pdptr = kvm_pdptr_read;
> context->inject_page_fault = kvm_inject_page_fault;
> }
> @@ -5207,7 +5211,7 @@ static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu,
> return;
>
> g_context->cpu_role.as_u64 = new_mode.as_u64;
> - g_context->get_guest_pgd = get_cr3;
> + g_context->get_guest_pgd = get_pgd;
> g_context->get_pdptr = kvm_pdptr_read;
> g_context->inject_page_fault = kvm_inject_page_fault;
>
> --
> 2.31.1
>
