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From: Brijesh Singh <brijesh.singh@amd.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>,
	Borislav Petkov <bp@suse.de>
Cc: brijesh.singh@amd.com, x86@kernel.org,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	"Tom Lendacky" <thomas.lendacky@amd.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>
Subject: Re: [PATCH v6 5/5] x86/kvm: Avoid dynamic allocation of pvclock data when SEV is active
Date: Mon, 10 Sep 2018 10:30:39 -0500	[thread overview]
Message-ID: <11618b8b-4d1f-9307-35f0-3c0f0fc856ca@amd.com> (raw)
In-Reply-To: <1536593297.11460.72.camel@intel.com>



On 09/10/2018 10:28 AM, Sean Christopherson wrote:
...

>>
>> IIRC, during guest creation time qemu will check the host supported
>> VCPUS count. If count is greater than KVM_MAX_VCPUS then it will
>> fail to launch guest (or fail to hot plug vcpus). In other words, the
>> number of vcpus in a KVM guest will never to > KVM_MAX_VCPUS.
>>
>> Am I missing something ?
> 
> KVM_MAX_VCPUS is a definition for use in the *host*, it's even defined
> in kvm_host.h.  The guest's pvclock code won't get magically recompiled
> if KVM_MAX_VCPUS is changed in the host.  KVM_MAX_VCPUS is an arbitrary
> value in the sense that there isn't a fundamental hard limit, i.e. the
> value can be changed, either for a custom KVM build or in mainline,
> e.g. it was bumped in 2016:
> 

Ah I see your point. thanks for clarifying it.



  reply	other threads:[~2018-09-10 15:30 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-07 17:57 [PATCH v6 0/5] x86: Fix SEV guest regression Brijesh Singh
2018-09-07 17:57 ` [PATCH v6 1/5] x86/mm: Restructure sme_encrypt_kernel() Brijesh Singh
2018-09-10 11:32   ` Borislav Petkov
2018-09-07 17:57 ` [PATCH v6 2/5] x86/mm: fix sme_populate_pgd() to update page flags Brijesh Singh
2018-09-10 11:36   ` Borislav Petkov
2018-09-10 12:28     ` Brijesh Singh
2018-09-10 12:32       ` Borislav Petkov
2018-09-07 17:57 ` [PATCH v6 3/5] x86/mm: add .data..decrypted section to hold shared variables Brijesh Singh
2018-09-10 11:54   ` Borislav Petkov
2018-09-10 12:33     ` Brijesh Singh
2018-09-07 17:57 ` [PATCH v6 4/5] x86/kvm: use __decrypted attribute in " Brijesh Singh
2018-09-10 12:04   ` Borislav Petkov
2018-09-10 13:15     ` Sean Christopherson
2018-09-10 13:29       ` Thomas Gleixner
2018-09-10 15:34       ` Borislav Petkov
2018-09-10 12:29   ` Paolo Bonzini
2018-09-10 12:33     ` Borislav Petkov
2018-09-10 12:46       ` Paolo Bonzini
2018-09-07 17:57 ` [PATCH v6 5/5] x86/kvm: Avoid dynamic allocation of pvclock data when SEV is active Brijesh Singh
2018-09-10 12:27   ` Borislav Petkov
2018-09-10 13:15     ` Brijesh Singh
2018-09-10 13:29       ` Sean Christopherson
2018-09-10 15:10         ` Brijesh Singh
2018-09-10 15:28           ` Sean Christopherson
2018-09-10 15:30             ` Brijesh Singh [this message]
2018-09-10 16:48               ` Borislav Petkov
2018-09-11  9:26                 ` Paolo Bonzini
2018-09-11 10:01                   ` Borislav Petkov
2018-09-11 10:19                     ` Paolo Bonzini
2018-09-11 10:25                       ` Borislav Petkov
2018-09-11 11:07                         ` Paolo Bonzini
2018-09-11 13:55                           ` Borislav Petkov
2018-09-11 14:00                             ` Paolo Bonzini
2018-09-10 15:53       ` Borislav Petkov
2018-09-10 16:13         ` Sean Christopherson
2018-09-10 16:14         ` Brijesh Singh
2018-09-10 12:28   ` Paolo Bonzini

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