From: Chao Gao <chao.gao@intel.com>
To: Zeng Guang <guang.zeng@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
H Peter Anvin <hpa@zytor.com>, <kvm@vger.kernel.org>,
<x86@kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/6] KVM: x86: Virtualize CR4.LASS
Date: Mon, 24 Apr 2023 15:32:36 +0800 [thread overview]
Message-ID: <ZEYwlMmzYnJjNNHq@chao-email> (raw)
In-Reply-To: <20230420133724.11398-2-guang.zeng@intel.com>
On Thu, Apr 20, 2023 at 09:37:19PM +0800, Zeng Guang wrote:
>Virtualize CR4.LASS[bit 27] under KVM control instead of being guest-owned
>as CR4.LASS generally set once for each vCPU at boot time and won't be
>toggled at runtime. Besides, only if VM has LASS capability enumerated with
>CPUID.(EAX=07H.ECX=1):EAX.LASS[bit 6], KVM allows guest software to be able
>to set CR4.LASS.
>By design CR4.LASS can be manipulated by nested guest as
>well.
This is inaccurate. The change in nested_vmx_cr_fixed1_bits_update() is
to allow L1 guests to set CR4.LASS in VMX operation. I would say:
Set the CR4.LASS bit in the emulated IA32_VMX_CR4_FIXED1 MSR for guests
to allow guests to enable LASS in nested VMX operation.
next prev parent reply other threads:[~2023-04-24 7:33 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-20 13:37 [PATCH 0/6] LASS KVM virtualization support Zeng Guang
2023-04-20 13:37 ` [PATCH 1/6] KVM: x86: Virtualize CR4.LASS Zeng Guang
2023-04-24 6:45 ` Binbin Wu
2023-04-25 1:52 ` Zeng Guang
2023-04-24 7:32 ` Chao Gao [this message]
2023-04-25 2:35 ` Zeng Guang
2023-04-25 3:26 ` Chao Gao
2023-04-20 13:37 ` [PATCH 2/6] KVM: VMX: Add new ops in kvm_x86_ops for LASS violation check Zeng Guang
2023-04-24 7:43 ` Binbin Wu
2023-04-25 3:26 ` Zeng Guang
2023-04-26 1:46 ` Binbin Wu
2023-04-25 3:10 ` Chao Gao
2023-04-25 7:31 ` Zeng Guang
2023-04-20 13:37 ` [PATCH 3/6] KVM: x86: Add emulator helper " Zeng Guang
2023-04-20 13:37 ` [PATCH 4/6] KVM: x86: LASS protection on KVM emulation when LASS enabled Zeng Guang
2023-04-25 2:52 ` Binbin Wu
2023-04-25 6:40 ` Zeng Guang
2023-04-26 1:31 ` Yuan Yao
2023-04-20 13:37 ` [PATCH 5/6] KVM: x86: Advertise LASS CPUID to user space Zeng Guang
2023-04-20 13:37 ` [PATCH 6/6] KVM: x86: Set KVM LASS based on hardware capability Zeng Guang
2023-04-25 2:57 ` Binbin Wu
2023-04-25 6:47 ` Zeng Guang
2023-04-25 7:28 ` Chao Gao
2023-04-24 1:20 ` [PATCH 0/6] LASS KVM virtualization support Binbin Wu
2023-04-25 1:49 ` Zeng Guang
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