linux-kernel - [PATCH 5.15 058/262] KVM: X86: Ensure that dirty PDPTRs are loaded

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Date:   Mon,  7 Mar 2022 10:16:42 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Lai Jiangshan <laijs@...ux.alibaba.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.15 058/262] KVM: X86: Ensure that dirty PDPTRs are loaded

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

[ Upstream commit 2c5653caecc4807b8abfe9c41880ac38417be7bf ]

For VMX with EPT, dirty PDPTRs need to be loaded before the next vmentry
via vmx_load_mmu_pgd()

But not all paths that call load_pdptrs() will cause vmx_load_mmu_pgd()
to be invoked.  Normally, kvm_mmu_reset_context() is used to cause
KVM_REQ_LOAD_MMU_PGD, but sometimes it is skipped:

* 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.

* 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.

* 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@...ux.alibaba.com>
Message-Id: <20211108124407.12187-2-jiangshanlai@...il.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/x86/kvm/x86.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 33cb065181248..33457b27e220b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -848,6 +848,7 @@ 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);
+	kvm_make_request(KVM_REQ_LOAD_MMU_PGD, vcpu);
 	vcpu->arch.pdptrs_from_userspace = false;
 
 out:
-- 
2.34.1