From: Matthew Rosato <mjrosato@linux.ibm.com>
To: Niklas Schnelle <schnelle@linux.ibm.com>,
Gerald Schaefer <gerald.schaefer@linux.ibm.com>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
Alex Williamson <alex.williamson@redhat.com>,
Gerd Bayer <gbayer@linux.ibm.com>, Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org
Subject: Re: [PATCH v2 1/3] s390/pci: Fix s390_mmio_read/write syscall page fault handling
Date: Tue, 28 May 2024 11:13:09 -0400 [thread overview]
Message-ID: <17c8e878-719b-45cb-b13c-73237024d333@linux.ibm.com> (raw)
In-Reply-To: <20240523-vfio_pci_mmap-v2-1-0dc6c139a4f1@linux.ibm.com>
On 5/23/24 7:10 AM, Niklas Schnelle wrote:
> The s390 MMIO syscalls when using the classic PCI instructions do not
> cause a page fault when follow_pte() fails due to the page not being
> present. Besides being a general deficiency this breaks vfio-pci's mmap()
> handling once VFIO_PCI_MMAP gets enabled as this lazily maps on first
> access. Fix this by following a failed follow_pte() with
> fixup_user_page() and retrying the follow_pte().
>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
FYI, as of -rc1 this patch has a merge conflict with 29ae7d96d166 ("mm: pass VMA instead of MM to follow_pte().")
next prev parent reply other threads:[~2024-05-28 15:13 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-23 11:10 [PATCH v2 0/3] vfio/pci: s390: Fix issues preventing VFIO_PCI_MMAP=y for s390 and enable it Niklas Schnelle
2024-05-23 11:10 ` [PATCH v2 1/3] s390/pci: Fix s390_mmio_read/write syscall page fault handling Niklas Schnelle
2024-05-28 15:12 ` Niklas Schnelle
2024-05-28 15:13 ` Matthew Rosato [this message]
2024-05-23 11:10 ` [PATCH v2 2/3] vfio/pci: Tolerate oversized BARs by disallowing mmap Niklas Schnelle
2024-05-28 15:13 ` Matthew Rosato
2024-05-23 11:10 ` [PATCH v2 3/3] vfio/pci: Enable PCI resource mmap() on s390 and remove VFIO_PCI_MMAP Niklas Schnelle
2024-05-23 15:19 ` Jason Gunthorpe
2024-05-28 15:14 ` Matthew Rosato
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