From: "Huang, Kai" <kai.huang@intel.com>
To: "Li, Xiaoyao" <xiaoyao.li@intel.com>,
"seanjc@google.com" <seanjc@google.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/3] KVM: x86: Fix supported VM_TYPES caps
Date: Fri, 26 Apr 2024 01:17:11 +0000 [thread overview]
Message-ID: <7f3001de041334b5c196b5436680473786a21816.camel@intel.com> (raw)
In-Reply-To: <ZippEkpjrEsGh5mj@google.com>
On Thu, 2024-04-25 at 07:30 -0700, Sean Christopherson wrote:
> On Thu, Apr 25, 2024, Xiaoyao Li wrote:
> > On 4/24/2024 12:53 AM, Sean Christopherson wrote:
> > > Fix a goof where KVM fails to re-initialize the set of supported VM types,
> > > resulting in KVM overreporting the set of supported types when a vendor
> > > module is reloaded with incompatible settings. E.g. unload kvm-intel.ko,
> > > reload with ept=0, and KVM will incorrectly treat SW_PROTECTED_VM as
> > > supported.
> >
> > Hah, this reminds me of the bug of msrs_to_save[] and etc.
> >
> > 7a5ee6edb42e ("KVM: X86: Fix initialization of MSR lists")
>
> Yeah, and we had the same bug with allow_smaller_maxphyaddr
>
> 88213da23514 ("kvm: x86: disable the narrow guest module parameter on unload")
>
> If the side effects of linking kvm.ko into kvm-{amd,intel}.ko weren't so painful
> for userspace,
>
Do we have any real side effects for _userspace_ here?
> I would more seriously consider pursuing that in advance of
> multi-KVM[*]. Because having KVM be fully self-contained has some *really* nice
> properties, e.g. eliminates this entire class of bugs, eliminates a huge pile of
> exports, etc.
>
> : > Since the symbols in the new module are invisible outside, I recommend:
> : > new kvm_intel.ko = kvm_intel.ko + kvm.ko
> : > new kvm_amd.ko = kvm_amd.ko + kvm.ko
> :
> : Yeah, Paolo also suggested this at LPC.
>
> [*] https://lore.kernel.org/all/ZWYtDGH5p4RpGYBw@google.com
>
+1. This makes life a lot easier.
next prev parent reply other threads:[~2024-04-26 1:18 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-23 16:53 [PATCH 0/3] KVM: x86: Fix supported VM_TYPES caps Sean Christopherson
2024-04-23 16:53 ` [PATCH 1/3] KVM: x86: Fully re-initialize supported_vm_types on vendor module load Sean Christopherson
2024-04-23 16:53 ` [PATCH 2/3] KVM: x86: Fully re-initialize supported_mce_cap " Sean Christopherson
2024-04-23 16:53 ` [PATCH 3/3] KVM: x86: Explicitly zero kvm_caps during " Sean Christopherson
2024-04-24 3:25 ` Huang, Kai
2024-04-24 15:33 ` Sean Christopherson
2024-04-25 10:07 ` Huang, Kai
2024-04-25 13:43 ` [PATCH 0/3] KVM: x86: Fix supported VM_TYPES caps Xiaoyao Li
2024-04-25 14:30 ` Sean Christopherson
2024-04-26 1:17 ` Huang, Kai [this message]
2024-04-26 15:47 ` Sean Christopherson
2024-04-29 2:45 ` Huang, Kai
2024-04-29 15:56 ` Sean Christopherson
2024-05-07 17:20 ` Paolo Bonzini
2024-05-07 17:08 ` Paolo Bonzini
2024-05-10 14:50 ` Paolo Bonzini
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