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From: "Liu, Jing2" <jing2.liu@linux.intel.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Derek Yerger <derek@djy.llc>,
	kernel@najdan.com, Thomas Lambertz <mail@thomaslambertz.de>,
	Rik van Riel <riel@surriel.com>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Borislav Petkov <bp@suse.de>, Dave Hansen <dave.hansen@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 0/4] KVM: x86: TIF_NEED_FPU_LOAD bug fixes
Date: Wed, 4 Mar 2020 15:38:44 +0800	[thread overview]
Message-ID: <32d432f7-bbdf-a240-7ee9-303d019d8d1a@linux.intel.com> (raw)
In-Reply-To: <20200117062628.6233-1-sean.j.christopherson@intel.com>


On 1/17/2020 2:26 PM, Sean Christopherson wrote:
> TIF_FPU_NEED_LOAD can be set any time
> control is transferred out of KVM, e.g. via IRQ->softirq, not just when
> KVM is preempted.

Hi Sean,

Is this just because kernel_fpu_begin() is called during softirq? I saw 
the dump trace in 3/4 message, but didn't find out clue.

Could I ask where kernel_fpu_begin() is called? Or is this just a 
"possible" thing?

Because I just want to make sure that, kvm can use this flag to cover 
all preempt/softirq/(other?) cases?

Thanks,

Jing


  parent reply	other threads:[~2020-03-04  7:38 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-17  6:26 [PATCH 0/4] KVM: x86: TIF_NEED_FPU_LOAD bug fixes Sean Christopherson
2020-01-17  6:26 ` [PATCH 1/4] KVM: x86: Handle TIF_NEED_FPU_LOAD in kvm_{load,put}_guest_fpu() Sean Christopherson
2020-01-17 18:31   ` Dave Hansen
2020-01-17 18:43     ` Sean Christopherson
2020-01-17  6:26 ` [PATCH 2/4] KVM: x86: Ensure guest's FPU state is loaded when accessing for emulation Sean Christopherson
2020-01-17  6:26 ` [PATCH 3/4] KVM: x86: Revert "KVM: X86: Fix fpu state crash in kvm guest" Sean Christopherson
2020-03-04  7:41   ` Liu, Jing2
2020-03-04  7:58     ` Paolo Bonzini
2020-01-17  6:26 ` [PATCH 4/4] KVM: x86: Remove unused ctxt param from emulator's FPU accessors Sean Christopherson
2020-03-04  7:38 ` Liu, Jing2 [this message]
2020-03-04 15:24   ` [PATCH 0/4] KVM: x86: TIF_NEED_FPU_LOAD bug fixes Sean Christopherson

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