From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: linuxppc-dev@lists.ozlabs.org, Nicholas Piggin <npiggin@gmail.com>
Cc: Timothy Pearson <tpearson@raptorengineering.com>
Subject: Re: [PATCH] KVM: PPC: Book3S HV: Fix KVM_RUN clobbering FP/VEC user registers
Date: Sun, 03 Dec 2023 10:00:37 +1100 [thread overview]
Message-ID: <170155803785.146803.4946329954526131755.b4-ty@ellerman.id.au> (raw)
In-Reply-To: <20231122025811.2973-1-npiggin@gmail.com>
On Wed, 22 Nov 2023 12:58:11 +1000, Nicholas Piggin wrote:
> Before running a guest, the host process (e.g., QEMU) FP/VEC registers
> are saved if they were being used, similarly to when the kernel uses FP
> registers. The guest values are then be loaded into regs, and the host
> process registers will be restored lazily when it uses FP/VEC.
>
> KVM HV has a bug here: the host process registers do get saved, but the
> user MSR bits remain enabled, which indicates the registers are valid
> for the process. After they are clobbered by running the guest, this
> valid indication causes the host process to take on the FP/VEC regiter
> values of the guest.
>
> [...]
Applied to powerpc/fixes.
[1/1] KVM: PPC: Book3S HV: Fix KVM_RUN clobbering FP/VEC user registers
https://git.kernel.org/powerpc/c/dc158d23b33df9033bcc8e7117e8591dd2f9d125
cheers
prev parent reply other threads:[~2023-12-02 23:03 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-22 2:58 [PATCH] KVM: PPC: Book3S HV: Fix KVM_RUN clobbering FP/VEC user registers Nicholas Piggin
2023-12-02 23:00 ` Michael Ellerman [this message]
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