From: Sean Christopherson <seanjc@google.com>
To: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Cc: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Bandan Das <bsd@redhat.com>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH v3] KVM: nVMX: Advertise ENCLS_EXITING to L1 iff SGX is fully supported
Date: Wed, 26 Oct 2022 16:53:21 +0000 [thread overview]
Message-ID: <Y1lmASxiV0r2Ldfs@google.com> (raw)
In-Reply-To: <20221026072330.2248336-1-eesposit@redhat.com>
On Wed, Oct 26, 2022, Emanuele Giuseppe Esposito wrote:
> Clear enable_sgx if ENCLS-exiting is not supported, i.e. if SGX cannot be
> virtualized. This fixes a bug where KVM would advertise ENCLS-exiting to
> L1 and propagate the control from vmcs12 to vmcs02 even if ENCLS-exiting
> isn't supported in secondary execution controls, e.g. because SGX isn't
> fully enabled, and thus induce an unexpected VM-Fail in L1.
>
> Not updating enable_sgx is responsible for a second bug:
> vmx_set_cpu_caps() doesn't clear the SGX bits when hardware support is
> unavailable. This is a much less problematic bug as it only pops up
> if SGX is soft-disabled (the case being handled by cpu_has_sgx()) or if
> SGX is supported for bare metal but not in the VMCS (will never happen
> when running on bare metal, but can theoertically happen when running in
> a VM).
>
> Last but not least, KVM should ideally have module params reflect KVM's
> actual configuration.
>
> RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=2127128
>
> Fixes: 72add915fbd5 ("KVM: VMX: Enable SGX virtualization for SGX1, SGX2 and LC")
> Cc: stable@vger.kernel.org
>
> Suggested-by: Sean Christopherson <seanjc@google.com>
> Suggested-by: Bandan Das <bsd@redhat.com>
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
> ---
Reviewed-by: Sean Christopherson <seanjc@google.com>
prev parent reply other threads:[~2022-10-26 16:53 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-26 7:23 [PATCH v3] KVM: nVMX: Advertise ENCLS_EXITING to L1 iff SGX is fully supported Emanuele Giuseppe Esposito
2022-10-26 16:53 ` Sean Christopherson [this message]
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