From: Kai Huang <kai.huang@intel.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@intel.com>,
linux-sgx@vger.kernel.org, kvm@vger.kernel.org, x86@kernel.org,
jarkko@kernel.org, luto@kernel.org, haitao.huang@intel.com,
pbonzini@redhat.com, tglx@linutronix.de, mingo@redhat.com,
hpa@zytor.com
Subject: Re: [RFC PATCH 04/23] x86/cpufeatures: Add SGX1 and SGX2 sub-features
Date: Wed, 13 Jan 2021 14:05:21 +1300 [thread overview]
Message-ID: <728ebce2384e15e9a376bd9dd08648794e2a0d36.camel@intel.com> (raw)
In-Reply-To: <X/4t+6JcyTGVEG2e@google.com>
On Tue, 2021-01-12 at 15:17 -0800, Sean Christopherson wrote:
> On Wed, Jan 13, 2021, Kai Huang wrote:
> > On Tue, 2021-01-12 at 18:51 +0100, Borislav Petkov wrote:
> > > On Tue, Jan 12, 2021 at 09:15:52AM -0800, Sean Christopherson wrote:
> > > > We want the boot_cpu_data.x86_capability memcpy() so that KVM doesn't advertise
> > > > support for features that are intentionally disabled in the kernel, e.g. via
> > > > kernel params. Except for a few special cases, e.g. LA57, KVM doesn't enable
> > > > features in the guest if they're disabled in the host, even if the features are
> > > > supported in hardware.
> > > >
> > > > For some features, e.g. SMEP and SMAP, honoring boot_cpu_data is mostly about
> > > > respecting the kernel's wishes, i.e. barring hardware bugs, enabling such
> > > > features in the guest won't break anything. But for other features, e.g. XSAVE
> > > > based features, enabling them in the guest without proper support in the host
> > > > will corrupt guest and/or host state.
> > >
> > > Ah ok, that is an important point.
> > >
> > > > So it's really the CPUID read that is (mostly) superfluous.
> > >
> > > Yeah, but that is cheap, as we established.
> > >
> > > Ok then, I don't see anything that might be a problem and I guess we can
> > > try that handling of scattered bits in kvm and see how far we'll get.
> >
> > Hi Sean, Boris,
> >
> > Thanks for all your feedback.
> >
> > Sean,
> >
> > Do you want to send me your patch (so that with your SoB), or do you want me to copy
> > & paste the code you posted in this series, plus Suggested-by you? Or how do you want
> > to proceed?
> >
> > Also to me it is better to separate X86_FEATURE_SGX1/2 with rest of KVM changes?
>
> Hmm, I'll split the changes into two proper patches and send them to you off list.
Thanks.
>
> > And do you think adding a dedicated, i.e. kvm_scattered_cpu_caps[], instead of using
> > existing kvm_cpu_cap[NCAPINTS] would be helpful to solve the problem caused by adding
> > new leaf to x86 core (see my another reply in this thread)?
>
> Probably not, because then we'd have to add new helpers to deal with the new
> array, or change all the helpers to take the array as a pointer. Blasting past
> NCAPINTS is a little evil, but it does slot in nicely to the existing code.
Sure. Thanks.
next prev parent reply other threads:[~2021-01-13 1:05 UTC|newest]
Thread overview: 111+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-06 1:55 [RFC PATCH 00/23] KVM SGX virtualization support Kai Huang
2021-01-06 1:55 ` [RFC PATCH 01/23] x86/sgx: Split out adding EPC page to free list to separate helper Kai Huang
2021-01-11 22:38 ` Jarkko Sakkinen
2021-01-12 0:19 ` Kai Huang
2021-01-12 21:45 ` Sean Christopherson
2021-01-13 1:15 ` Kai Huang
2021-01-13 17:05 ` Jarkko Sakkinen
2021-01-06 1:55 ` [RFC PATCH 02/23] x86/sgx: Add enum for SGX_CHILD_PRESENT error code Kai Huang
2021-01-06 18:28 ` Dave Hansen
2021-01-06 21:40 ` Kai Huang
2021-01-12 0:26 ` Jarkko Sakkinen
2021-01-11 23:32 ` Jarkko Sakkinen
2021-01-12 0:16 ` Kai Huang
2021-01-12 1:46 ` Jarkko Sakkinen
2021-01-06 1:55 ` [RFC PATCH 03/23] x86/sgx: Introduce virtual EPC for use by KVM guests Kai Huang
2021-01-06 19:35 ` Dave Hansen
2021-01-06 20:35 ` Sean Christopherson
2021-01-07 0:47 ` Kai Huang
2021-01-07 0:52 ` Dave Hansen
2021-01-07 1:38 ` Kai Huang
2021-01-07 5:00 ` Dave Hansen
2021-01-07 1:42 ` Kai Huang
2021-01-07 5:02 ` Dave Hansen
2021-01-15 14:07 ` Kai Huang
2021-01-15 15:39 ` Dave Hansen
2021-01-15 21:33 ` Kai Huang
2021-01-15 21:45 ` Sean Christopherson
2021-01-15 22:30 ` Kai Huang
2021-01-11 23:38 ` Jarkko Sakkinen
2021-01-12 0:56 ` Kai Huang
2021-01-12 1:50 ` Jarkko Sakkinen
2021-01-12 2:03 ` Kai Huang
2021-01-06 1:55 ` [RFC PATCH 04/23] x86/cpufeatures: Add SGX1 and SGX2 sub-features Kai Huang
2021-01-06 19:39 ` Dave Hansen
2021-01-06 22:12 ` Kai Huang
2021-01-06 22:21 ` Dave Hansen
2021-01-06 22:56 ` Kai Huang
2021-01-06 23:19 ` Sean Christopherson
2021-01-06 23:33 ` Dave Hansen
2021-01-06 23:56 ` Kai Huang
2021-01-06 23:40 ` Kai Huang
2021-01-06 23:43 ` Dave Hansen
2021-01-06 23:56 ` Kai Huang
2021-01-06 22:15 ` Borislav Petkov
2021-01-06 23:09 ` Kai Huang
2021-01-07 6:41 ` Borislav Petkov
2021-01-08 2:00 ` Kai Huang
2021-01-08 5:10 ` Dave Hansen
2021-01-08 7:03 ` Kai Huang
2021-01-08 7:17 ` Borislav Petkov
2021-01-08 8:06 ` Kai Huang
2021-01-08 8:13 ` Borislav Petkov
2021-01-08 9:00 ` Kai Huang
2021-01-08 23:55 ` Sean Christopherson
2021-01-09 0:35 ` Borislav Petkov
2021-01-09 1:01 ` Sean Christopherson
2021-01-09 1:19 ` Borislav Petkov
2021-01-11 17:54 ` Sean Christopherson
2021-01-11 19:09 ` Borislav Petkov
2021-01-11 19:20 ` Sean Christopherson
2021-01-12 2:01 ` Kai Huang
2021-01-12 12:13 ` Borislav Petkov
2021-01-12 17:15 ` Sean Christopherson
2021-01-12 17:51 ` Borislav Petkov
2021-01-12 21:07 ` Kai Huang
2021-01-12 23:17 ` Sean Christopherson
2021-01-13 1:05 ` Kai Huang [this message]
2021-01-11 23:39 ` Jarkko Sakkinen
2021-01-06 1:55 ` [RFC PATCH 05/23] x86/cpu/intel: Allow SGX virtualization without Launch Control support Kai Huang
2021-01-06 19:54 ` Dave Hansen
2021-01-06 22:34 ` Kai Huang
2021-01-06 22:38 ` Dave Hansen
2021-01-06 1:56 ` [RFC PATCH 06/23] x86/sgx: Expose SGX architectural definitions to the kernel Kai Huang
2021-01-06 1:56 ` [RFC PATCH 07/23] x86/sgx: Move ENCLS leaf definitions to sgx_arch.h Kai Huang
2021-01-06 1:56 ` [RFC PATCH 08/23] x86/sgx: Add SGX2 ENCLS leaf definitions (EAUG, EMODPR and EMODT) Kai Huang
2021-01-06 1:56 ` [RFC PATCH 09/23] x86/sgx: Add encls_faulted() helper Kai Huang
2021-01-06 1:56 ` [RFC PATCH 10/23] x86/sgx: Add helper to update SGX_LEPUBKEYHASHn MSRs Kai Huang
2021-01-06 19:56 ` Dave Hansen
2021-01-06 1:56 ` [RFC PATCH 11/23] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM Kai Huang
2021-01-06 20:12 ` Dave Hansen
2021-01-06 21:04 ` Sean Christopherson
2021-01-06 21:23 ` Dave Hansen
2021-01-06 22:58 ` Kai Huang
2021-01-06 1:56 ` [RFC PATCH 12/23] x86/sgx: Move provisioning device creation out of SGX driver Kai Huang
2021-01-06 1:56 ` [RFC PATCH 13/23] KVM: VMX: Convert vcpu_vmx.exit_reason to a union Kai Huang
2021-01-06 1:56 ` [RFC PATCH 14/23] KVM: x86: Export kvm_mmu_gva_to_gpa_{read,write}() for SGX (VMX) Kai Huang
2021-01-06 1:56 ` [RFC PATCH 15/23] KVM: x86: Define new #PF SGX error code bit Kai Huang
2021-01-06 1:56 ` [RFC PATCH 16/23] KVM: x86: Add SGX feature leaf to reverse CPUID lookup Kai Huang
2021-01-06 1:56 ` [RFC PATCH 17/23] KVM: VMX: Add basic handling of VM-Exit from SGX enclave Kai Huang
2021-01-06 1:56 ` [RFC PATCH 18/23] KVM: VMX: Frame in ENCLS handler for SGX virtualization Kai Huang
2021-01-06 1:56 ` [RFC PATCH 19/23] KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions Kai Huang
2021-01-06 1:56 ` [RFC PATCH 20/23] KVM: VMX: Add emulation of SGX Launch Control LE hash MSRs Kai Huang
2021-01-06 1:56 ` [RFC PATCH 21/23] KVM: VMX: Add ENCLS[EINIT] handler to support SGX Launch Control (LC) Kai Huang
2021-01-06 1:56 ` [RFC PATCH 22/23] KVM: VMX: Enable SGX virtualization for SGX1, SGX2 and LC Kai Huang
2021-01-06 1:58 ` [RFC PATCH 23/23] KVM: x86: Add capability to grant VM access to privileged SGX attribute Kai Huang
2021-01-06 2:22 ` [RFC PATCH 00/23] KVM SGX virtualization support Kai Huang
2021-01-06 17:07 ` Dave Hansen
2021-01-07 0:34 ` Kai Huang
2021-01-07 0:48 ` Dave Hansen
2021-01-07 1:50 ` Kai Huang
2021-01-07 16:14 ` Sean Christopherson
2021-01-08 2:16 ` Kai Huang
2021-01-11 17:20 ` Jarkko Sakkinen
2021-01-11 18:37 ` Sean Christopherson
2021-01-12 1:58 ` Jarkko Sakkinen
2021-01-12 1:14 ` Kai Huang
2021-01-12 2:02 ` Jarkko Sakkinen
2021-01-12 2:07 ` Kai Huang
2021-01-15 14:43 ` Kai Huang
2021-01-16 9:31 ` Jarkko Sakkinen
2021-01-16 9:50 ` Jarkko Sakkinen
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