From: Lai Jiangshan <jiangshanlai@gmail.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Paolo Bonzini <pbonzini@redhat.com>
Cc: Lai Jiangshan <laijs@linux.alibaba.com>,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>
Subject: [PATCH] KVM: X86: Raise #GP when clearing CR0_PG in 64 bit mode
Date: Tue, 7 Dec 2021 17:52:30 +0800 [thread overview]
Message-ID: <20211207095230.53437-1-jiangshanlai@gmail.com> (raw)
From: Lai Jiangshan <laijs@linux.alibaba.com>
In the SDM:
If the logical processor is in 64-bit mode or if CR4.PCIDE = 1, an
attempt to clear CR0.PG causes a general-protection exception (#GP).
Software should transition to compatibility mode and clear CR4.PCIDE
before attempting to disable paging.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
---
arch/x86/kvm/x86.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 00f5b2b82909..78c40ac3b197 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -906,7 +906,8 @@ int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
!load_pdptrs(vcpu, kvm_read_cr3(vcpu)))
return 1;
- if (!(cr0 & X86_CR0_PG) && kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE))
+ if (!(cr0 & X86_CR0_PG) &&
+ (is_64_bit_mode(vcpu) || kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE)))
return 1;
static_call(kvm_x86_set_cr0)(vcpu, cr0);
--
2.19.1.6.gb485710b
next reply other threads:[~2021-12-07 9:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-07 9:52 Lai Jiangshan [this message]
2021-12-09 17:55 ` [PATCH] KVM: X86: Raise #GP when clearing CR0_PG in 64 bit mode Paolo Bonzini
2025-06-07 0:58 ` H. Peter Anvin
2025-06-09 14:23 ` Sean Christopherson
2025-06-09 18:16 ` Jim Mattson
2025-06-09 18:20 ` Jim Mattson
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