From: Sean Christopherson <seanjc@google.com>
To: Tyler Stachecki <stachecki.tyler@gmail.com>
Cc: Leonardo Bras <leobras@redhat.com>,
Dongli Zhang <dongli.zhang@oracle.com>,
kvm@vger.kernel.org, pbonzini@redhat.com, dgilbert@redhat.com,
tglx@linutronix.de, mingo@redhat.com,
dave.hansen@linux.intel.com, bp@alien8.de,
Tyler Stachecki <tstachecki@bloomberg.net>,
stable@vger.kernel.org
Subject: Re: [PATCH] x86/kvm: Account for fpstate->user_xfeatures changes
Date: Tue, 26 Sep 2023 10:31:51 -0700 [thread overview]
Message-ID: <ZRMVh0CMmfMo3kmc@google.com> (raw)
In-Reply-To: <ZRMHY83W/VPjYyhy@google.com>
On Tue, Sep 26, 2023, Sean Christopherson wrote:
> Masking fpstate->user_xfeatures is buggy for another reason: it's destructive if
> userspace calls KVM_SET_CPUID multiple times. No real world userspace actually
> calls KVM_SET_CPUID to "expand" features, but it's technically possible and KVM
> is supposed to allow it.
This particular bit is wrong, KVM overwrites user_xfeatures, it doesn't AND it.
I misremembered the code.
next prev parent reply other threads:[~2023-09-26 17:31 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-14 1:00 [PATCH] x86/kvm: Account for fpstate->user_xfeatures changes Tyler Stachecki
2023-09-14 1:33 ` Tyler Stachecki
2023-09-14 7:15 ` Leonardo Bras
2023-09-14 9:11 ` Tyler Stachecki
2023-09-14 17:05 ` Dongli Zhang
2023-09-15 0:58 ` Tyler Stachecki
2023-09-15 7:41 ` Leonardo Bras
2023-09-15 12:27 ` Tyler Stachecki
2023-09-25 21:26 ` Sean Christopherson
2023-09-26 3:02 ` Tyler Stachecki
2023-09-26 16:31 ` Sean Christopherson
2023-09-26 17:31 ` Sean Christopherson [this message]
2023-09-26 19:22 ` Sean Christopherson
2023-09-26 20:27 ` Sean Christopherson
2023-09-15 7:13 ` Leonardo Bras
2023-09-15 7:11 ` Leonardo Bras
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