linux-kernel - Re: [PATCH 0/3] KVM: x86: Fix supported VM

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Message-ID: <4a66f882-12bf-4a07-a80a-a1600e89a103@intel.com>
Date: Thu, 25 Apr 2024 21:43:20 +0800
From: Xiaoyao Li <xiaoyao.li@...el.com>
To: Sean Christopherson <seanjc@...gle.com>,
 Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/3] KVM: x86: Fix supported VM_TYPES caps

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")

The series looks good to me.

With v2 to move the reset of kvm_cap and set the
hardcoded caps earlier,

Reviewed-by: Xiaoyao Li <xiaoyao.li@...el.com>

> Fix a similar long-standing bug with supported_mce_cap that is much less
> benign, and then harden against us making the same mistake in the future.
 >
> Sean Christopherson (3):
>    KVM: x86: Fully re-initialize supported_vm_types on vendor module load
>    KVM: x86: Fully re-initialize supported_mce_cap on vendor module load
>    KVM: x86: Explicitly zero kvm_caps during vendor module load
> 
>   arch/x86/kvm/x86.c | 15 +++++++++++----
>   1 file changed, 11 insertions(+), 4 deletions(-)
> 
> 
> base-commit: a96cb3bf390eebfead5fc7a2092f8452a7997d1b