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From: Paolo Bonzini <pbonzini@redhat.com>
To: Yang Weijiang <weijiang.yang@intel.com>,
	seanjc@google.com, jmattson@google.com, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org
Cc: yu.c.zhang@linux.intel.com
Subject: Re: [PATCH v15 07/14] KVM: VMX: Emulate reads and writes to CET MSRs
Date: Wed, 3 Feb 2021 12:57:41 +0100	[thread overview]
Message-ID: <6a743d57-8128-b5db-ddc1-9dd4c4c1004e@redhat.com> (raw)
In-Reply-To: <20210203113421.5759-8-weijiang.yang@intel.com>

On 03/02/21 12:34, Yang Weijiang wrote:
> MSRs that are switched through XSAVES are especially annoying due to 
> the possibility of the kernel's FPU being used in IRQ context. Disable 
> IRQs and ensure the guest's FPU state is loaded when accessing such MSRs.

Good catch!  This should be in x86.h and named kvm_get/set_xsave_msr 
because it's not VMX specific.  The commit message should also be there 
as a comment.

In addition,

> +	case MSR_IA32_S_CET:
> +		if (!cet_is_control_msr_accessible(vcpu, msr_info))
> +			return 1;
> +		msr_info->data = vmcs_readl(GUEST_S_CET);
> +		break;
> +	case MSR_IA32_U_CET:
> +		if (!cet_is_control_msr_accessible(vcpu, msr_info))
> +			return 1;
> +		vmx_get_xsave_msr(msr_info);
> +		break;

these two might as well be the same "case" for symmetry with the 
handling of WRMSR.

I've fixed this up locally, since these patches will not be pushed to 
Linus until the corresponding bare metal support is there.

Paolo


  reply	other threads:[~2021-02-03 11:59 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-03 11:34 [PATCH v15 00/14] Introduce support for guest CET feature Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 01/14] KVM: x86: Report XSS as an MSR to be saved if there are supported features Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 02/14] KVM: x86: Refresh CPUID on writes to MSR_IA32_XSS Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 03/14] KVM: x86: Load guest fpu state when accessing MSRs managed by XSAVES Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 04/14] KVM: x86: Add #CP support in guest exception dispatch Yang Weijiang
2021-02-03 21:46   ` Sean Christopherson
2021-02-04  7:22     ` Yang Weijiang
2021-02-04  8:28       ` Paolo Bonzini
2021-02-04  8:24     ` Paolo Bonzini
2021-02-04 16:42       ` Sean Christopherson
2021-02-04 17:29         ` Paolo Bonzini
2021-02-03 11:34 ` [PATCH v15 05/14] KVM: VMX: Introduce CET VMCS fields and flags Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 06/14] KVM: x86: Add fault checks for CR4.CET Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 07/14] KVM: VMX: Emulate reads and writes to CET MSRs Yang Weijiang
2021-02-03 11:57   ` Paolo Bonzini [this message]
2021-02-03 12:50     ` Yang Weijiang
2022-05-18 15:55   ` John Allen
2022-05-18 16:16     ` Sean Christopherson
2022-05-19  8:49       ` Yang, Weijiang
2021-02-03 11:34 ` [PATCH v15 08/14] KVM: VMX: Add a synthetic MSR to allow userspace VMM to access GUEST_SSP Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 09/14] KVM: x86: Report CET MSRs as to-be-saved if CET is supported Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 10/14] KVM: x86: Enable CET virtualization for VMX and advertise CET to userspace Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 11/14] KVM: VMX: Pass through CET MSRs to the guest when supported Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 12/14] KVM: nVMX: Add helper to check the vmcs01 MSR bitmap for MSR pass-through Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 13/14] KVM: nVMX: Enable CET support for nested VMX Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 14/14] KVM: x86: Save/Restore GUEST_SSP to/from SMRAM Yang Weijiang
2021-02-03 12:07   ` Paolo Bonzini
2021-02-03 12:59     ` Yang Weijiang
2021-02-03 12:40 ` [PATCH v15 00/14] Introduce support for guest CET feature Paolo Bonzini

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