From: Lai Jiangshan <jiangshanlai@gmail.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Lai Jiangshan <laijs@linux.alibaba.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Yu Zhang <yu.c.zhang@linux.intel.com>,
Paolo Bonzini <pbonzini@redhat.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>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>
Subject: [RFC PATCH 1/2] kvm/x86: intercept guest changes to X86_CR4_LA57
Date: Mon, 28 Sep 2020 16:30:46 +0800 [thread overview]
Message-ID: <20200928083047.3349-1-jiangshanlai@gmail.com> (raw)
From: Lai Jiangshan <laijs@linux.alibaba.com>
When shadowpaping is enabled, guest should not be allowed
to toggle X86_CR4_LA57. And X86_CR4_LA57 is a rarely changed
bit, so we can just intercept all the attempts to toggle it
no matter shadowpaping is in used or not.
Fixes: fd8cb433734ee ("KVM: MMU: Expose the LA57 feature to VM.")
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Yu Zhang <yu.c.zhang@linux.intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
---
No test to toggle X86_CR4_LA57 in guest since I can't access to
any CPU supports it. Maybe it is not a real problem.
arch/x86/kvm/kvm_cache_regs.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h
index cfe83d4ae625..ca0781b41df9 100644
--- a/arch/x86/kvm/kvm_cache_regs.h
+++ b/arch/x86/kvm/kvm_cache_regs.h
@@ -7,7 +7,7 @@
#define KVM_POSSIBLE_CR0_GUEST_BITS X86_CR0_TS
#define KVM_POSSIBLE_CR4_GUEST_BITS \
(X86_CR4_PVI | X86_CR4_DE | X86_CR4_PCE | X86_CR4_OSFXSR \
- | X86_CR4_OSXMMEXCPT | X86_CR4_LA57 | X86_CR4_PGE | X86_CR4_TSD)
+ | X86_CR4_OSXMMEXCPT | X86_CR4_PGE | X86_CR4_TSD)
#define BUILD_KVM_GPR_ACCESSORS(lname, uname) \
static __always_inline unsigned long kvm_##lname##_read(struct kvm_vcpu *vcpu)\
--
2.19.1.6.gb485710b
next reply other threads:[~2020-09-28 7:30 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-28 8:30 Lai Jiangshan [this message]
2020-09-28 8:30 ` [RFC PATCH 2/2] kvm/x86: allow guest to toggle X86_CR4_FSGSBASE Lai Jiangshan
2020-09-28 16:24 ` [RFC PATCH 1/2] kvm/x86: intercept guest changes to X86_CR4_LA57 Sean Christopherson
2020-09-29 5:32 ` Lai Jiangshan
2020-09-29 8:32 ` Sean Christopherson
2020-09-29 8:45 ` Lai Jiangshan
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