From: Paolo Bonzini <pbonzini@redhat.com>
To: "Liu, Jing2" <jing2.liu@intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"bp@alien8.de" <bp@alien8.de>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>
Cc: "Christopherson,, Sean" <seanjc@google.com>,
"Nakajima, Jun" <jun.nakajima@intel.com>,
"Tian, Kevin" <kevin.tian@intel.com>,
"jing2.liu@linux.intel.com" <jing2.liu@linux.intel.com>,
"Zeng, Guang" <guang.zeng@intel.com>,
"Wang, Wei W" <wei.w.wang@intel.com>,
"Zhong, Yang" <yang.zhong@intel.com>
Subject: Re: [PATCH v2 23/23] kvm: x86: Disable RDMSR interception of IA32_XFD_ERR
Date: Tue, 21 Dec 2021 09:48:30 +0100 [thread overview]
Message-ID: <f465ec18-4a0d-2e1c-239e-cc93aa43226f@redhat.com> (raw)
In-Reply-To: <MWHPR11MB12451924FE9189E4B69E78A4A97C9@MWHPR11MB1245.namprd11.prod.outlook.com>
On 12/21/21 07:29, Liu, Jing2 wrote:
>>
> Thanks for reviewing the patches.
>
> If disable unconditionally in vmx_create_vcpu, it means even guest has
> no cpuid, the msr read is passthrough to guest and it can read a value, which
> seems strange, though spec doesn't mention the read behaviour w/o cpuid.
>
> How about disabling read interception at vmx_vcpu_after_set_cpuid?
>
> if (boot_cpu_has(X86_FEATURE_XFD) && guest_cpuid_has(vcpu, X86_FEATURE_XFD))
> vmx_set_intercept_for_msr(vcpu, MSR_IA32_XFD_ERR, MSR_TYPE_R, false);
Even better:
if (boot_cpu_has(X86_FEATURE_XFD))
vmx_set_intercept_for_msr(vcpu, MSR_IA32_XFD_ERR, MSR_TYPE_R,
!guest_cpuid_has(vcpu, X86_FEATURE_XFD));
Thanks,
Paolo
next prev parent reply other threads:[~2021-12-21 8:48 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-17 15:29 [PATCH v2 00/23] AMX Support in KVM Jing Liu
2021-12-17 15:29 ` [PATCH v2 01/23] x86/fpu: Extend fpu_xstate_prctl() with guest permissions Jing Liu
2021-12-17 18:45 ` Thomas Gleixner
2021-12-17 18:47 ` Thomas Gleixner
2021-12-17 15:29 ` [PATCH v2 02/23] x86/fpu: Prepare guest FPU for dynamically enabled FPU features Jing Liu
2021-12-17 15:29 ` [PATCH v2 03/23] kvm: x86: Fix xstate_required_size() to follow XSTATE alignment rule Jing Liu
2021-12-17 15:29 ` [PATCH v2 04/23] kvm: x86: Exclude unpermitted xfeatures at KVM_GET_SUPPORTED_CPUID Jing Liu
2021-12-20 13:20 ` Paolo Bonzini
2021-12-17 15:29 ` [PATCH v2 05/23] kvm: x86: Check permitted dynamic xfeatures at KVM_SET_CPUID2 Jing Liu
2021-12-17 15:29 ` [PATCH v2 06/23] x86/fpu: Make XFD initialization in __fpstate_reset() a function argument Jing Liu
2021-12-17 15:29 ` [PATCH v2 07/23] x86/fpu: Add guest support to xfd_enable_feature() Jing Liu
2021-12-17 15:29 ` [PATCH v2 08/23] x86/fpu: Provide fpu_update_guest_perm_features() for guest Jing Liu
2021-12-17 18:50 ` Thomas Gleixner
2021-12-17 15:29 ` [PATCH v2 09/23] kvm: x86: Enable dynamic XSAVE features at KVM_SET_CPUID2 Jing Liu
2021-12-17 15:29 ` [PATCH v2 10/23] x86/fpu: Provide fpu_update_guest_xfd() for IA32_XFD emulation Jing Liu
2021-12-17 15:29 ` [PATCH v2 11/23] kvm: x86: Add emulation for IA32_XFD Jing Liu
2021-12-17 15:29 ` [PATCH v2 12/23] x86/fpu: Prepare xfd_err in struct fpu_guest Jing Liu
2021-12-17 15:29 ` [PATCH v2 13/23] kvm: x86: Intercept #NM for saving IA32_XFD_ERR Jing Liu
2021-12-17 15:29 ` [PATCH v2 14/23] kvm: x86: Emulate IA32_XFD_ERR for guest Jing Liu
2021-12-17 15:29 ` [PATCH v2 15/23] kvm: x86: Add XCR0 support for Intel AMX Jing Liu
2021-12-17 15:29 ` [PATCH v2 16/23] kvm: x86: Add CPUID " Jing Liu
2021-12-17 15:29 ` [PATCH v2 17/23] x86/fpu: add uabi_size to guest_fpu Jing Liu
2021-12-17 15:29 ` [PATCH v2 18/23] kvm: x86: Get/set expanded xstate buffer Jing Liu
2021-12-20 9:04 ` Paolo Bonzini
2021-12-21 2:45 ` Wang, Wei W
2021-12-21 8:45 ` Paolo Bonzini
2021-12-21 9:06 ` Wang, Wei W
2021-12-21 9:30 ` Paolo Bonzini
2021-12-17 15:29 ` [PATCH v2 19/23] kvm: selftests: Add support for KVM_CAP_XSAVE2 Jing Liu
2021-12-20 13:19 ` Paolo Bonzini
2021-12-17 15:30 ` [PATCH v2 20/23] docs: kvm: Add KVM_GET_XSAVE2 Jing Liu
2021-12-20 9:04 ` Paolo Bonzini
2021-12-17 15:30 ` [PATCH v2 21/23] x86/fpu: Provide fpu_sync_guest_vmexit_xfd_state() Jing Liu
2021-12-17 15:30 ` [PATCH v2 22/23] kvm: x86: Disable interception for IA32_XFD on demand Jing Liu
2021-12-20 9:07 ` Paolo Bonzini
2021-12-21 6:42 ` Liu, Jing2
2021-12-21 8:46 ` Paolo Bonzini
2021-12-17 15:30 ` [PATCH v2 23/23] kvm: x86: Disable RDMSR interception of IA32_XFD_ERR Jing Liu
2021-12-20 9:08 ` Paolo Bonzini
2021-12-21 6:29 ` Liu, Jing2
2021-12-21 8:48 ` Paolo Bonzini [this message]
2021-12-21 9:00 ` Liu, Jing2
2021-12-21 9:05 ` Paolo Bonzini
2021-12-17 18:52 ` [PATCH v2 00/23] AMX Support in KVM Thomas Gleixner
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