From: Bandan Das <bsd@redhat.com>
To: kvm <kvm@vger.kernel.org>
Subject: x86: Don't report guest userspace emulation error to userspace, why ?
Date: Wed, 09 Dec 2015 17:18:32 -0500 [thread overview]
Message-ID: <jpg6107gtaf.fsf@linux.bootlegged.copy> (raw)
Commit a2b9e6c1a35afcc09:
KVM: x86: Don't report guest userspace emulation error to userspace
Commit fc3a9157d314 ("KVM: X86: Don't report L2 emulation failures to
user-space") disabled the reporting of L2 (nested guest) emulation failures to
userspace due to race-condition between a vmexit and the instruction emulator.
The same rational applies also to userspace applications that are permitted by
the guest OS to access MMIO area or perform PIO.
This patch extends the current behavior - of injecting a #UD instead of
reporting it to userspace - also for guest userspace code.
I searched the archives but failed in finding anything. Can someone please
explain why this is needed ? Or, why not let userspace decide what to do based
on the cpl, whether to continue execution or kill the guest ? Is the assumption
here that this is what userspace always wants ?
next reply other threads:[~2015-12-09 22:18 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-09 22:18 Bandan Das [this message]
2015-12-10 9:12 ` x86: Don't report guest userspace emulation error to userspace, why ? Paolo Bonzini
2015-12-10 17:58 ` Bandan Das
2015-12-10 17:59 ` Paolo Bonzini
2015-12-10 18:36 ` Bandan Das
2015-12-10 20:20 ` Paolo Bonzini
2015-12-10 20:35 ` Bandan Das
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