From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <seanjc@google.com>,
Ashish Kalra <Ashish.Kalra@amd.com>
Cc: 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 v13 10/12] KVM: x86: Introduce new KVM_FEATURE_SEV_LIVE_MIGRATION feature & Custom MSR.
Date: Tue, 20 Apr 2021 12:49:41 +0200 [thread overview]
Message-ID: <988e38b4-2f69-ff66-eac9-e1714c049867@redhat.com> (raw)
In-Reply-To: <YH4M5guOafToCWd7@google.com>
On 20/04/21 01:06, Sean Christopherson wrote:
>> diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h
>> index 950afebfba88..f6bfa138874f 100644
>> --- a/arch/x86/include/uapi/asm/kvm_para.h
>> +++ b/arch/x86/include/uapi/asm/kvm_para.h
>> @@ -33,6 +33,7 @@
>> #define KVM_FEATURE_PV_SCHED_YIELD 13
>> #define KVM_FEATURE_ASYNC_PF_INT 14
>> #define KVM_FEATURE_MSI_EXT_DEST_ID 15
>> +#define KVM_FEATURE_SEV_LIVE_MIGRATION 16
>>
>> #define KVM_HINTS_REALTIME 0
>>
>> @@ -54,6 +55,7 @@
>> #define MSR_KVM_POLL_CONTROL 0x4b564d05
>> #define MSR_KVM_ASYNC_PF_INT 0x4b564d06
>> #define MSR_KVM_ASYNC_PF_ACK 0x4b564d07
>> +#define MSR_KVM_SEV_LIVE_MIGRATION 0x4b564d08
>>
>> struct kvm_steal_time {
>> __u64 steal;
>> @@ -136,4 +138,6 @@ struct kvm_vcpu_pv_apf_data {
>> #define KVM_PV_EOI_ENABLED KVM_PV_EOI_MASK
>> #define KVM_PV_EOI_DISABLED 0x0
>>
>> +#define KVM_SEV_LIVE_MIGRATION_ENABLED BIT_ULL(0)
>
> Even though the intent is to "force" userspace to intercept the MSR, I think KVM
> should at least emulate the legal bits as a nop. Deferring completely to
> userspace is rather bizarre as there's not really anything to justify KVM
> getting involved. It would also force userspace to filter the MSR just to
> support the hypercall.
I think this is the intention, the hypercall by itself cannot do much if
you cannot tell userspace that it's up-to-date.
On the other hand it is kind of wrong that KVM_GET_SUPPORTED_CPUID
returns the feature, but the MSR is not supported.
> Somewhat of a nit, but I think we should do something like s/ENABLED/READY,
Agreed. I'll send a patch that puts everything together.
Paolo
next prev parent reply other threads:[~2021-04-20 10:50 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-15 15:52 [PATCH v13 00/12] Add AMD SEV guest live migration support Ashish Kalra
2021-04-15 15:53 ` [PATCH v13 01/12] KVM: SVM: Add KVM_SEV SEND_START command Ashish Kalra
2021-04-20 8:50 ` Paolo Bonzini
2021-04-15 15:53 ` [PATCH v13 02/12] KVM: SVM: Add KVM_SEND_UPDATE_DATA command Ashish Kalra
2021-04-15 15:54 ` [PATCH v13 03/12] KVM: SVM: Add KVM_SEV_SEND_FINISH command Ashish Kalra
2021-04-15 15:54 ` [PATCH v13 04/12] KVM: SVM: Add support for KVM_SEV_RECEIVE_START command Ashish Kalra
2021-04-20 8:38 ` Paolo Bonzini
2021-04-20 9:18 ` Paolo Bonzini
2021-04-15 15:55 ` [PATCH v13 05/12] KVM: SVM: Add KVM_SEV_RECEIVE_UPDATE_DATA command Ashish Kalra
2021-04-20 8:40 ` Paolo Bonzini
2021-04-20 8:43 ` Paolo Bonzini
2021-04-15 15:55 ` [PATCH v13 06/12] KVM: SVM: Add KVM_SEV_RECEIVE_FINISH command Ashish Kalra
2021-04-15 15:56 ` [PATCH v13 07/12] KVM: x86: Add AMD SEV specific Hypercall3 Ashish Kalra
2021-04-15 15:57 ` [PATCH v13 08/12] KVM: X86: Introduce KVM_HC_PAGE_ENC_STATUS hypercall Ashish Kalra
2021-04-20 11:10 ` Paolo Bonzini
2021-04-20 17:24 ` Sean Christopherson
2021-04-15 15:57 ` [PATCH v13 09/12] mm: x86: Invoke hypercall when page encryption status is changed Ashish Kalra
2021-04-20 9:39 ` Paolo Bonzini
2021-04-21 10:05 ` Borislav Petkov
2021-04-21 12:00 ` Paolo Bonzini
2021-04-21 14:09 ` Borislav Petkov
2021-04-21 12:12 ` Ashish Kalra
2021-04-21 13:50 ` Brijesh Singh
2021-04-21 13:52 ` Borislav Petkov
2021-04-15 15:58 ` [PATCH v13 10/12] KVM: x86: Introduce new KVM_FEATURE_SEV_LIVE_MIGRATION feature & Custom MSR Ashish Kalra
2021-04-19 23:06 ` Sean Christopherson
2021-04-20 10:49 ` Paolo Bonzini [this message]
2021-04-20 9:47 ` Paolo Bonzini
2021-04-15 15:58 ` [PATCH v13 11/12] EFI: Introduce the new AMD Memory Encryption GUID Ashish Kalra
2021-04-15 16:01 ` [PATCH v13 12/12] x86/kvm: Add guest support for detecting and enabling SEV Live Migration feature Ashish Kalra
2021-04-20 10:52 ` Paolo Bonzini
2021-04-21 14:44 ` Borislav Petkov
2021-04-21 15:22 ` Ashish Kalra
2021-04-21 15:32 ` Borislav Petkov
2021-04-21 15:38 ` Paolo Bonzini
2021-04-21 18:48 ` Ashish Kalra
2021-04-21 19:19 ` Ashish Kalra
2021-04-16 21:43 ` [PATCH v13 00/12] Add AMD SEV guest live migration support Steve Rutherford
2021-04-19 14:40 ` Ashish Kalra
2021-04-20 11:11 ` Paolo Bonzini
2021-04-20 18:51 ` Borislav Petkov
2021-04-20 19:08 ` Paolo Bonzini
2021-04-20 20:28 ` Borislav Petkov
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