[PATCH 01/15] KVM: X86: Ensure the dirty PDPTEs to be loaded

Lai Jiangshan
2021-11-08T12:44:18Z

From: Lai Jiangshan <laijs@linux.alibaba.com>

For VMX, the dirty PDPTEs needs to be loaded before the coming VMENTER
via vmx_load_mmu_pgd() if EPT is enabled.

But not all paths that call load_pdptrs() will cause vmx_load_mmu_pgd()
to be invoked. Normally, kvm_mmu_reset_context() and KVM_REQ_LOAD_MMU_PGD
are used to launch later vmx_load_mmu_pgd().

The commit d81135a57aa6("KVM: x86: do not reset mmu if CR0.CD and
CR0.NW are changed") skips kvm_mmu_reset_context() after load_pdptrs()
when changing CR0.CD and CR0.NW.

The commit 21823fbda552("KVM: x86: Invalidate all PGDs for the current
PCID on MOV CR3 w/ flush") skips KVM_REQ_LOAD_MMU_PGD after
load_pdptrs() when rewriting the CR3 with the same value.

The commit a91a7c709600("KVM: X86: Don't reset mmu context when
toggling X86_CR4_PGE") skips kvm_mmu_reset_context() after
load_pdptrs() when changing CR4.PGE.

Fixes: d81135a57aa6("KVM: x86: do not reset mmu if CR0.CD and CR0.NW are changed")
Fixes: 21823fbda552("KVM: x86: Invalidate all PGDs for the current PCID on MOV CR3 w/ flush")
Fixes: a91a7c709600("KVM: X86: Don't reset mmu context when toggling X86_CR4_PGE")
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
---
arch/x86/kvm/x86.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ac83d873d65b..034c233ea5a1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -830,6 +830,8 @@ int load_pdptrs(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, unsigned long cr3)

memcpy(mmu->pdptrs, pdpte, sizeof(mmu->pdptrs));
kvm_register_mark_dirty(vcpu, VCPU_EXREG_PDPTR);
+ /* Ensure the dirty PDPTEs to be loaded. */
+ kvm_make_request(KVM_REQ_LOAD_MMU_PGD, vcpu);
vcpu->arch.pdptrs_from_userspace = false;

return 1;
--
2.19.1.6.gb485710b