From: Jason Gunthorpe <jgg@ziepe.ca>
To: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: 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>,
Matthew Rosato <mjrosato@linux.ibm.com>,
linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org
Subject: Re: [PATCH 1/3] s390/pci: Fix s390_mmio_read/write syscall page fault handling
Date: Wed, 22 May 2024 20:18:52 -0300 [thread overview]
Message-ID: <20240522231852.GF69273@ziepe.ca> (raw)
In-Reply-To: <20240521-vfio_pci_mmap-v1-1-2f6315e0054e@linux.ibm.com>
On Tue, May 21, 2024 at 02:14:57PM +0200, 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().
>
> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
> ---
> arch/s390/pci/pci_mmio.c | 18 +++++++++++++-----
> 1 file changed, 13 insertions(+), 5 deletions(-)
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Jason
next prev parent reply other threads:[~2024-05-22 23:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-21 12:14 [PATCH 0/3] vfio/pci: s390: Fix issues preventing VFIO_PCI_MMAP=y for s390 and enable it Niklas Schnelle
2024-05-21 12:14 ` [PATCH 1/3] s390/pci: Fix s390_mmio_read/write syscall page fault handling Niklas Schnelle
2024-05-22 23:18 ` Jason Gunthorpe [this message]
2024-05-21 12:14 ` [PATCH 2/3] vfio/pci: Tolerate oversized BARs by disallowing mmap Niklas Schnelle
2024-05-22 23:19 ` Jason Gunthorpe
2024-05-21 12:14 ` [PATCH 3/3] vfio/pci: Enable VFIO_PCI_MMAP for s390 Niklas Schnelle
2024-05-22 23:20 ` Jason Gunthorpe
2024-05-23 8:24 ` Niklas Schnelle
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