From: "Tian, Kevin" <kevin.tian@intel.com>
To: "Christopherson,, Sean" <seanjc@google.com>,
"Zhong, Yang" <yang.zhong@intel.com>
Cc: "x86@kernel.org" <x86@kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
"linux-kselftest@vger.kernel.org"
<linux-kselftest@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>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"corbet@lwn.net" <corbet@lwn.net>,
"shuah@kernel.org" <shuah@kernel.org>,
"Nakajima, Jun" <jun.nakajima@intel.com>,
"jing2.liu@linux.intel.com" <jing2.liu@linux.intel.com>,
"Liu, Jing2" <jing2.liu@intel.com>,
"Zeng, Guang" <guang.zeng@intel.com>,
"Wang, Wei W" <wei.w.wang@intel.com>
Subject: RE: [PATCH v4 12/21] kvm: x86: Intercept #NM for saving IA32_XFD_ERR
Date: Wed, 5 Jan 2022 00:27:09 +0000 [thread overview]
Message-ID: <BN9PR11MB5276B533C168E2DE3AE7D0718C4B9@BN9PR11MB5276.namprd11.prod.outlook.com> (raw)
In-Reply-To: <YdSnlmO4dUnwRxxc@google.com>
> From: Sean Christopherson <seanjc@google.com>
> Sent: Wednesday, January 5, 2022 4:01 AM
>
> On Wed, Dec 29, 2021, Yang Zhong wrote:
> > +static void handle_nm_fault_irqoff(struct kvm_vcpu *vcpu)
> > +{
> > + rdmsrl(MSR_IA32_XFD_ERR, vcpu->arch.guest_fpu.xfd_err);
> > + kvm_queue_exception(vcpu, NM_VECTOR);
>
> This is still wrong, even though no additional supported is needed to support
> nested XFD. If L1 wants to intercept #NM, then KVM must not inject the #NM
> and
> must not read XFD_ERR.
Sure. This v4 was sent out before we settled down this open in v3
discussion. We did fix it later and posted the sample logic here:
https://lore.kernel.org/all/BN9PR11MB52767789D59239DF5DD524758C469@BN9PR11MB5276.namprd11.prod.outlook.com/
Will include this fix in v5.
Thanks
Kevin
next prev parent reply other threads:[~2022-01-05 0:27 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-29 13:13 [PATCH v4 00/21] AMX Support in KVM Yang Zhong
2021-12-29 13:13 ` [PATCH v4 01/21] x86/fpu: Extend fpu_xstate_prctl() with guest permissions Yang Zhong
2021-12-29 13:13 ` [PATCH v4 02/21] x86/fpu: Prepare guest FPU for dynamically enabled FPU features Yang Zhong
2021-12-29 13:13 ` [PATCH v4 03/21] kvm: x86: Fix xstate_required_size() to follow XSTATE alignment rule Yang Zhong
2022-01-04 19:54 ` Sean Christopherson
2021-12-29 13:13 ` [PATCH v4 04/21] kvm: x86: Exclude unpermitted xfeatures at KVM_GET_SUPPORTED_CPUID Yang Zhong
2021-12-29 13:13 ` [PATCH v4 05/21] x86/fpu: Make XFD initialization in __fpstate_reset() a function argument Yang Zhong
2021-12-29 13:13 ` [PATCH v4 06/21] x86/fpu: Add guest support to xfd_enable_feature() Yang Zhong
2021-12-29 13:13 ` [PATCH v4 07/21] x86/fpu: Provide fpu_update_guest_perm_features() for guest Yang Zhong
2021-12-29 13:13 ` [PATCH v4 08/21] kvm: x86: Check and enable permitted dynamic xfeatures at KVM_SET_CPUID2 Yang Zhong
2021-12-29 16:55 ` Sean Christopherson
2021-12-30 2:28 ` Tian, Kevin
2021-12-29 13:13 ` [PATCH v4 09/21] x86/fpu: Provide fpu_update_guest_xfd() for IA32_XFD emulation Yang Zhong
2021-12-29 13:13 ` [PATCH v4 10/21] kvm: x86: Add emulation for IA32_XFD Yang Zhong
2022-01-04 19:32 ` Sean Christopherson
2022-01-05 0:22 ` Tian, Kevin
2021-12-29 13:13 ` [PATCH v4 11/21] x86/fpu: Prepare xfd_err in struct fpu_guest Yang Zhong
2021-12-29 13:13 ` [PATCH v4 12/21] kvm: x86: Intercept #NM for saving IA32_XFD_ERR Yang Zhong
2022-01-04 20:01 ` Sean Christopherson
2022-01-05 0:27 ` Tian, Kevin [this message]
2021-12-29 13:13 ` [PATCH v4 13/21] kvm: x86: Emulate IA32_XFD_ERR for guest Yang Zhong
2021-12-29 13:13 ` [PATCH v4 14/21] kvm: x86: Disable RDMSR interception of IA32_XFD_ERR Yang Zhong
2022-01-04 19:34 ` Sean Christopherson
2022-01-05 0:23 ` Tian, Kevin
2021-12-29 13:13 ` [PATCH v4 15/21] kvm: x86: Add XCR0 support for Intel AMX Yang Zhong
2021-12-29 13:13 ` [PATCH v4 16/21] kvm: x86: Add CPUID " Yang Zhong
2021-12-29 13:13 ` [PATCH v4 17/21] x86/fpu: Add uabi_size to guest_fpu Yang Zhong
2021-12-29 13:13 ` [PATCH v4 18/21] kvm: x86: Add support for getting/setting expanded xstate buffer Yang Zhong
2022-01-04 19:46 ` Sean Christopherson
2022-01-04 20:45 ` Paolo Bonzini
2022-01-05 4:03 ` Tian, Kevin
2021-12-29 13:13 ` [PATCH v4 19/21] kvm: selftests: Add support for KVM_CAP_XSAVE2 Yang Zhong
2021-12-29 13:13 ` [PATCH v4 20/21] x86/fpu: Provide fpu_sync_guest_vmexit_xfd_state() Yang Zhong
2021-12-29 13:13 ` [PATCH v4 21/21] kvm: x86: Disable interception for IA32_XFD on demand Yang Zhong
2021-12-30 8:46 ` [PATCH v4 00/21] AMX Support in KVM Tian, Kevin
2022-01-04 18:36 ` Paolo Bonzini
2022-01-04 18:54 ` Sean Christopherson
2022-01-05 0:10 ` Tian, Kevin
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