From: Sean Christopherson <seanjc@google.com>
To: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Cc: "pbonzini@redhat.com" <pbonzini@redhat.com>,
"jmattson@google.com" <jmattson@google.com>,
"joro@8bytes.org" <joro@8bytes.org>,
"vkuznets@redhat.com" <vkuznets@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"thomas.lendacky@amd.com" <thomas.lendacky@amd.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"brijesh.singh@amd.com" <brijesh.singh@amd.com>,
"wanpengli@tencent.com" <wanpengli@tencent.com>
Subject: Re: [PATCH 07/12] KVM: x86: SEV: Treat C-bit as legal GPA bit regardless of vCPU mode
Date: Wed, 3 Feb 2021 18:19:31 -0800 [thread overview]
Message-ID: <YBtZs4Z2ROeHyf3m@google.com> (raw)
In-Reply-To: <5fa85e81a54800737a1417be368f0061324e0aec.camel@intel.com>
On Thu, Feb 04, 2021, Edgecombe, Rick P wrote:
> On Wed, 2021-02-03 at 16:01 -0800, Sean Christopherson wrote:
> >
> > - unsigned long cr3_lm_rsvd_bits;
> > + u64 reserved_gpa_bits;
>
> LAM defines bits above the GFN in CR3:
> https://software.intel.com/content/www/us/en/develop/download/intel-architecture-instruction-set-extensions-programming-reference.html
>
> KVM doesn't support this today of course, but it might be confusing to
> try to combine the two concepts.
Ah, took me a few minutes, but I see what you're saying. LAM will introduce
bits that are repurposed for CR3, but not generic GPAs. And, the behavior is
based on CPU support, so it'd make sense to have a mask cached in vcpu->arch
as opposed to constantly generating it on the fly.
Definitely agree that having a separate cr3_lm_rsvd_bits or whatever is the
right way to go when LAM comes along. Not sure it's worth keeping a duplicate
field in the meantime, though it would avoid a small amount of thrash.
Paolo, any thoughts?
next prev parent reply other threads:[~2021-02-04 2:20 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-04 0:01 [PATCH 00/12] KVM: x86: Legal GPA fixes and cleanups Sean Christopherson
2021-02-04 0:01 ` [PATCH 01/12] KVM: x86: Set so called 'reserved CR3 bits in LM mask' at vCPU reset Sean Christopherson
2021-02-04 0:01 ` [PATCH 02/12] KVM: nSVM: Don't strip host's C-bit from guest's CR3 when reading PDPTRs Sean Christopherson
2021-02-04 0:01 ` [PATCH 03/12] KVM: x86: Add a helper to check for a legal GPA Sean Christopherson
2021-02-04 0:01 ` [PATCH 04/12] KVM: x86: Add a helper to handle legal GPA with an alignment requirement Sean Christopherson
2021-02-04 0:01 ` [PATCH 05/12] KVM: VMX: Use GPA legality helpers to replace open coded equivalents Sean Christopherson
2021-02-04 0:01 ` [PATCH 06/12] KVM: nSVM: Use common GPA helper to check for illegal CR3 Sean Christopherson
2021-02-04 0:01 ` [PATCH 07/12] KVM: x86: SEV: Treat C-bit as legal GPA bit regardless of vCPU mode Sean Christopherson
2021-02-04 2:03 ` Edgecombe, Rick P
2021-02-04 2:19 ` Sean Christopherson [this message]
2021-02-04 10:34 ` Paolo Bonzini
2021-02-04 17:31 ` Edgecombe, Rick P
2021-02-04 17:52 ` Sean Christopherson
2021-02-04 17:56 ` Paolo Bonzini
2021-02-04 18:01 ` Sean Christopherson
2021-02-04 0:01 ` [PATCH 08/12] KVM: x86: Use reserved_gpa_bits to calculate reserved PxE bits Sean Christopherson
2021-02-04 0:01 ` [PATCH 09/12] KVM: x86/mmu: Add helper to generate mask of reserved HPA bits Sean Christopherson
2021-02-04 0:01 ` [PATCH 10/12] KVM: x86: Add helper to consolidate "raw" reserved GPA mask calculations Sean Christopherson
2021-02-04 0:01 ` [PATCH 11/12] KVM: x86: Move nVMX's consistency check macro to common code Sean Christopherson
2021-02-04 0:01 ` [PATCH 12/12] KVM: nSVM: Trace VM-Enter consistency check failures Sean Christopherson
2021-02-04 10:44 ` [PATCH 00/12] KVM: x86: Legal GPA fixes and cleanups Paolo Bonzini
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