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From: Peter Zijlstra <peterz@infradead.org>
To: Yang Weijiang <weijiang.yang@intel.com>
Cc: pbonzini@redhat.com, seanjc@google.com, x86@kernel.org,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	rick.p.edgecombe@intel.com,
	Sean Christopherson <sean.j.christopherson@intel.com>
Subject: Re: [PATCH 16/19] KVM: x86: Enable CET virtualization for VMX and advertise CET to userspace
Date: Thu, 16 Jun 2022 12:59:01 +0200	[thread overview]
Message-ID: <YqsM9VkQ4cTSJ4Ct@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20220616084643.19564-17-weijiang.yang@intel.com>

On Thu, Jun 16, 2022 at 04:46:40AM -0400, Yang Weijiang wrote:
> Set the feature bits so that CET capabilities can be seen in guest via
> CPUID enumeration. Add CR4.CET bit support in order to allow guest set CET
> master control bit(CR4.CET).
> 
> Disable KVM CET feature if unrestricted_guest is unsupported/disabled as
> KVM does not support emulating CET.
> 
> Don't expose CET feature if dependent CET bits are cleared in host XSS,
> or if XSAVES isn't supported.  Updating the CET features in common x86 is
> a little ugly, but there is no clean solution without risking breakage of
> SVM if SVM hardware ever gains support for CET, e.g. moving everything to
> common x86 would prematurely expose CET on SVM.  The alternative is to
> put all the logic in VMX, but that means rereading host_xss in VMX and
> duplicating the XSAVES check across VMX and SVM.

Doesn't Zen3 already have SHSTK ?

  reply	other threads:[~2022-06-16 10:59 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-16  8:46 [PATCH 00/19] Refresh queued CET virtualization series Yang Weijiang
2022-06-16  8:46 ` [PATCH 01/19] x86/cet/shstk: Add Kconfig option for Shadow Stack Yang Weijiang
2022-06-16  8:46 ` [PATCH 02/19] x86/cpufeatures: Add CPU feature flags for shadow stacks Yang Weijiang
2022-06-16  8:46 ` [PATCH 03/19] x86/cpufeatures: Enable CET CR4 bit for shadow stack Yang Weijiang
2022-06-16 10:24   ` Peter Zijlstra
2022-06-16 17:12     ` Edgecombe, Rick P
2022-06-17 11:38       ` Peter Zijlstra
2022-06-17 21:18         ` Edgecombe, Rick P
2022-06-16 10:25   ` Peter Zijlstra
2022-06-16 17:36     ` Edgecombe, Rick P
2022-06-16  8:46 ` [PATCH 04/19] x86/fpu/xstate: Introduce CET MSR and XSAVES supervisor states Yang Weijiang
2022-06-16 10:27   ` Peter Zijlstra
2022-06-16 17:12     ` Edgecombe, Rick P
2022-06-16  8:46 ` [PATCH 05/19] x86/fpu: Add helper for modifying xstate Yang Weijiang
2022-06-16  8:46 ` [PATCH 06/19] KVM: x86: Report XSS as an MSR to be saved if there are supported features Yang Weijiang
2022-06-16  8:46 ` [PATCH 07/19] KVM: x86: Refresh CPUID on writes to MSR_IA32_XSS Yang Weijiang
2022-06-16  8:46 ` [PATCH 08/19] KVM: x86: Load guest fpu state when accessing MSRs managed by XSAVES Yang Weijiang
2022-06-16  8:46 ` [PATCH 09/19] KVM: x86: Add #CP support in guest exception classification Yang Weijiang
2022-06-16  8:46 ` [PATCH 10/19] KVM: VMX: Introduce CET VMCS fields and flags Yang Weijiang
2022-06-16  8:46 ` [PATCH 11/19] KVM: x86: Add fault checks for CR4.CET Yang Weijiang
2022-06-16  8:46 ` [PATCH 12/19] KVM: VMX: Emulate reads and writes to CET MSRs Yang Weijiang
2022-06-16  8:46 ` [PATCH 13/19] KVM: VMX: Add a synthetic MSR to allow userspace VMM to access GUEST_SSP Yang Weijiang
2022-06-16  8:46 ` [PATCH 14/19] KVM: x86: Report CET MSRs as to-be-saved if CET is supported Yang Weijiang
2022-06-16  8:46 ` [PATCH 15/19] KVM: x86: Save/Restore GUEST_SSP to/from SMM state save area Yang Weijiang
2022-06-16  8:46 ` [PATCH 16/19] KVM: x86: Enable CET virtualization for VMX and advertise CET to userspace Yang Weijiang
2022-06-16 10:59   ` Peter Zijlstra [this message]
2022-06-16 15:27     ` Yang, Weijiang
2022-06-25  6:55     ` Yang, Weijiang
2022-06-16  8:46 ` [PATCH 17/19] KVM: VMX: Pass through CET MSRs to the guest when supported Yang Weijiang
2022-06-16  8:46 ` [PATCH 18/19] KVM: nVMX: Enable CET support for nested VMX Yang Weijiang
2022-06-16  8:46 ` [PATCH 19/19] KVM: x86: Enable supervisor IBT support for guest Yang Weijiang
2022-06-16 11:05   ` Peter Zijlstra
2022-06-16 11:19   ` Peter Zijlstra
2022-06-16 15:56     ` Yang, Weijiang
2022-06-16  9:10 ` [PATCH 00/19] Refresh queued CET virtualization series Christoph Hellwig
2022-06-16 11:25   ` Peter Zijlstra
2022-06-16 10:12 ` Peter Zijlstra
2022-06-16 10:21   ` Paolo Bonzini
2022-06-16 14:18     ` Peter Zijlstra
2022-06-16 15:06       ` Yang, Weijiang
2022-06-16 15:28       ` Paolo Bonzini
2022-06-18  6:43         ` Yang, Weijiang
2022-07-14 19:36           ` Sean Christopherson
2022-07-15 15:04             ` Yang, Weijiang
2022-07-15 15:58               ` Sean Christopherson

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