From: Paolo Bonzini <pbonzini@redhat.com>
To: Rik van Riel <riel@redhat.com>, David Hildenbrand <david@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
tglx@linutronix.de, rkrcmar@redhat.com, borntraeger@de.ibm.com
Subject: Re: [PATCH] x86,kvm: move qemu/guest FPU switching out to vcpu_run
Date: Tue, 14 Nov 2017 19:09:17 +0100 [thread overview]
Message-ID: <d5beb041-9a21-84b3-9b72-a8aa7cfb0e2e@redhat.com> (raw)
In-Reply-To: <1510682877.30057.1.camel@redhat.com>
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On 14/11/2017 19:07, Rik van Riel wrote:
> My question is, can the in-kernel emulator code ever
> be called from OUTSIDE the KVM_RUN ioctl loop?
No, it can't. This makes the patch much more appealing...
Paolo
> If so, we need to restore the user FPU context before
> returning from the emulator code. Given that the current
> emulator code does not do that, I suspect this is not
> the case. I also see no path from the kvm ioctl into
> the emulator code, other than via KVM_RUN.
>
> The FPU and XSAVE ioctls all work on the saved
> vcpu->arch.guest_fpu data, and never directly on the
> registers.
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next prev parent reply other threads:[~2017-11-14 18:09 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-14 5:12 [PATCH] x86,kvm: move qemu/guest FPU switching out to vcpu_run Rik van Riel
2017-11-14 16:57 ` David Hildenbrand
2017-11-14 18:07 ` Rik van Riel
2017-11-14 18:09 ` Paolo Bonzini [this message]
2017-11-14 19:40 ` David Hildenbrand
2017-11-14 21:11 ` Rik van Riel
2017-11-15 8:34 ` Paolo Bonzini
2017-11-15 9:23 ` David Hildenbrand
2017-11-15 14:50 ` Rik van Riel
2017-11-15 15:20 ` David Hildenbrand
2017-12-04 2:15 ` Wanpeng Li
2017-12-05 17:09 ` Radim Krcmar
2017-12-06 2:48 ` Wanpeng Li
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