From: Mathias Krause <minipli@grsecurity.net>
To: "Xiaoyao Li" <xiaoyao.li@intel.com>,
"Daniel P. Berrangé" <berrange@redhat.com>
Cc: qemu-devel@nongnu.org, Paolo Bonzini <pbonzini@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
kvm@vger.kernel.org, Oliver Upton <oliver.upton@linux.dev>,
Sean Christopherson <seanjc@google.com>
Subject: Re: [PATCH] i386/kvm: Disable hypercall patching quirk by default
Date: Tue, 22 Jul 2025 22:13:06 +0200 [thread overview]
Message-ID: <834dd439-34dd-4cc7-a1cb-ffe3b95ec460@grsecurity.net> (raw)
In-Reply-To: <c2d2a3e9-e317-4049-9b6d-b6b3027ddd6d@intel.com>
On 22.07.25 14:21, Xiaoyao Li wrote:
> On 7/22/2025 7:15 PM, Daniel P. Berrangé wrote:
>> [...]
>>
>> Usually CSPs don't have full control over what their customers
>> are running as a guest. If their customers are running mainstream
>> modern guest OS, CONFIG_STRICT_KERNEL_RWX is pretty likely to be
>> set, so presumably migration between Intel & AMD will not work
>> and this isn't making it worse ?
>
> If breaking some usecase is not a concern, then I'm fine with no compat
> property.
Well, there's still the chicken bit `-accel kvm,hypercall-patching=on`
one could make use of if (and really only if) that's really needed. But
I'd rather have the guest see a proper exception emulation of trying to
execute an unsupported instruction than seeing a bogus #PF.
Thanks,
Mathias
next prev parent reply other threads:[~2025-07-22 20:13 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-19 19:42 [PATCH] i386/kvm: Disable hypercall patching quirk by default Mathias Krause
2025-07-21 10:22 ` Mathias Krause
2025-07-22 3:45 ` Xiaoyao Li
2025-07-22 9:21 ` Mathias Krause
2025-07-22 10:27 ` Xiaoyao Li
2025-07-22 10:35 ` Mohamed Mediouni
2025-07-22 11:06 ` Xiaoyao Li
2025-07-22 11:16 ` Mohamed Mediouni
2025-07-22 11:15 ` Daniel P. Berrangé
2025-07-22 12:21 ` Xiaoyao Li
2025-07-22 20:13 ` Mathias Krause [this message]
2025-07-22 20:08 ` Mathias Krause
2025-07-23 9:26 ` David Woodhouse
2025-08-04 9:35 ` Mathias Krause
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