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From: Alex Williamson <alex.williamson@redhat.com>
To: Derek Yerger <derek@djy.llc>
Cc: kvm@vger.kernel.org, <sean.j.christopherson@intel.com>,
	"Bonzini, Paolo" <pbonzini@redhat.com>
Subject: Re: PROBLEM: Regression of MMU causing guest VM application errors
Date: Wed, 16 Oct 2019 11:28:57 -0600	[thread overview]
Message-ID: <20191016112857.293a197d@x1.home> (raw)
In-Reply-To: <1e525b08-6204-3238-5d56-513f82f1d7fb@djy.llc>

On Wed, 16 Oct 2019 00:49:51 -0400
Derek Yerger <derek@djy.llc> wrote:

> In at least Linux 5.2.7 via Fedora, up to 5.2.18, guest OS applications 
> repeatedly crash with segfaults. The problem does not occur on 5.1.16.
> 
> System is running Fedora 29 with kernel 5.2.18. Guest OS is Windows 10 with an 
> AMD Radeon 540 GPU passthrough. When on 5.2.7 or 5.2.18, specific windows 
> applications frequently and repeatedly crash, throwing exceptions in random 
> libraries. Going back to 5.1.16, the issue does not occur.
> 
> The host system is unaffected by the regression.
> 
> Keywords: kvm mmu pci passthrough vfio vfio-pci amdgpu
> 
> Possibly related: Unmerged [PATCH] KVM: x86/MMU: Zap all when removing memslot 
> if VM has assigned device

That was never merged because it was superseded by:

d012a06ab1d2 Revert "KVM: x86/mmu: Zap only the relevant pages when removing a memslot"

That revert also induced this commit:

002c5f73c508 KVM: x86/mmu: Reintroduce fast invalidate/zap for flushing memslot

Both of these were merged to stable, showing up in 5.2.11 and 5.2.16
respectively, so seeing these sorts of issues might be considered a
known issue on 5.2.7, but not 5.2.18 afaik.  Do you have a specific
test that reliably reproduces the issue?  Thanks,

Alex

  parent reply	other threads:[~2019-10-16 17:28 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-16  4:49 PROBLEM: Regression of MMU causing guest VM application errors Derek Yerger
2019-10-16  7:28 ` Paolo Bonzini
2019-10-16 17:28 ` Alex Williamson [this message]
2019-10-16 17:49   ` Sean Christopherson
2019-10-17 23:57     ` Derek Yerger
2019-10-22 20:28       ` Sean Christopherson
2019-10-24 15:18         ` Derek Yerger
2019-10-24 17:32           ` Sean Christopherson
2019-10-31  3:44             ` Derek Yerger
2019-11-19 20:01               ` Sean Christopherson
2019-11-20  9:19                 ` Wanpeng Li
2019-11-20  9:57                   ` Paolo Bonzini
2019-11-20 18:19                 ` Sean Christopherson
2019-11-20 19:04                   ` Derek Yerger
2019-11-20 19:28                     ` Sean Christopherson
2019-11-27 15:24                       ` Sean Christopherson
2019-12-17 23:11                         ` Sean Christopherson
2019-12-17 23:13                           ` Derek Yerger
2020-01-02 13:42                           ` Derek Yerger

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