From: Sean Christopherson <seanjc@google.com>
To: Ashish Kalra <Ashish.Kalra@amd.com>
Cc: pbonzini@redhat.com, tglx@linutronix.de, mingo@redhat.com,
hpa@zytor.com, joro@8bytes.org, bp@suse.de,
thomas.lendacky@amd.com, x86@kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, srutherford@google.com,
venu.busireddy@oracle.com, brijesh.singh@amd.com
Subject: Re: [PATCH 1/4] KVM: x86: Add AMD SEV specific Hypercall3
Date: Fri, 23 Apr 2021 00:03:31 +0000 [thread overview]
Message-ID: <YIIO0wtHeNK6pyri@google.com> (raw)
In-Reply-To: <c33adc91aa57df258821f78224c0a2b73591423a.1619124613.git.ashish.kalra@amd.com>
On Thu, Apr 22, 2021, Ashish Kalra wrote:
> From: Brijesh Singh <brijesh.singh@amd.com>
>
> KVM hypercall framework relies on alternative framework to patch the
> VMCALL -> VMMCALL on AMD platform. If a hypercall is made before
> apply_alternative() is called then it defaults to VMCALL. The approach
> works fine on non SEV guest. A VMCALL would causes #UD, and hypervisor
> will be able to decode the instruction and do the right things. But
> when SEV is active, guest memory is encrypted with guest key and
> hypervisor will not be able to decode the instruction bytes.
>
> Add SEV specific hypercall3, it unconditionally uses VMMCALL. The hypercall
> will be used by the SEV guest to notify encrypted pages to the hypervisor.
I still think we should invert the default and avoid having an SEV specific
variant of kvm_hypercall3().
https://lore.kernel.org/kvm/X8gyhCsEMf8QU9H%2F@google.com/
next prev parent reply other threads:[~2021-04-23 0:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-22 20:54 [PATCH 0/4] Add guest support for SEV live migration Ashish Kalra
2021-04-22 20:55 ` [PATCH 1/4] KVM: x86: Add AMD SEV specific Hypercall3 Ashish Kalra
2021-04-23 0:03 ` Sean Christopherson [this message]
2021-04-22 20:55 ` [PATCH 2/4] mm: x86: Invoke hypercall when page encryption status is changed Ashish Kalra
2021-04-22 20:56 ` [PATCH 3/4] EFI: Introduce the new AMD Memory Encryption GUID Ashish Kalra
2021-04-22 20:56 ` [PATCH 4/4] x86/kvm: Add guest support for detecting and enabling SEV Live Migration feature Ashish Kalra
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