[PATCH 3/9] KVM: x86: MMU: Rename get_cr3() --> get_pgd() and clear high bits for pgd

Robert Hoo
2022-10-17T07:05:40Z

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@linux.intel.com>
Reviewed-by: Jingqi Liu <jingqi.liu@intel.com>
---
arch/x86/include/asm/processor-flags.h | 1 +
arch/x86/kvm/mmu/mmu.c | 10 +++++-----
2 files changed, 6 insertions(+), 5 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 eccddb136954..385a1a9b1ac4 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4473,9 +4473,9 @@ 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)
{
- return kvm_read_cr3(vcpu);
+ return kvm_read_cr3(vcpu) & ~CR3_HIGH_RSVD_MASK;
}

static bool sync_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, gfn_t gfn,
@@ -5028,7 +5028,7 @@ 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;

@@ -5178,7 +5178,7 @@ 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;
}
@@ -5192,7 +5192,7 @@ 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