On Wed, Oct 16, 2019 at 11:28:57AM -0600, Alex Williamson wrote: > On Wed, 16 Oct 2019 00:49:51 -0400 > Derek Yerger <derek@xxxxxxx> 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 That was never merged because it was superseded by: 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, Also, does the failure reproduce on on 5.2.1 - 5.2.6? The memslot debacle exists on all flavors of 5.2.x, if the errors showed up in 5.2.7 then they are being caused by something else.
