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 3/3] vfio/pci: Enable PCI resource mmap() on s390 and remove VFIO_PCI_MMAP
Date: Tue, 28 May 2024 11:14:07 -0400 [thread overview]
Message-ID: <d80eec0d-6e84-41e6-b4fb-bbea06d0d6bc@linux.ibm.com> (raw)
In-Reply-To: <20240523-vfio_pci_mmap-v2-3-0dc6c139a4f1@linux.ibm.com>
On 5/23/24 7:10 AM, Niklas Schnelle wrote:
> With the introduction of memory I/O (MIO) instructions enbaled in commit
> 71ba41c9b1d9 ("s390/pci: provide support for MIO instructions") s390
> gained support for direct user-space access to mapped PCI resources.
> Even without those however user-space can access mapped PCI resources
> via the s390 specific MMIO syscalls. Thus mmap() can and should be
> supported on all s390 systems with native PCI. Since VFIO_PCI_MMAP
> enablement for s390 would make it unconditionally true and thus
> pointless just remove it entirely.
>
> Link: https://lore.kernel.org/all/c5ba134a1d4f4465b5956027e6a4ea6f6beff969.camel@linux.ibm.com/
> Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Also sanity tested on s390 with mlx, nvme, ISM over vfio-pci (the latter of which triggers the patch 2 scenario).
prev parent reply other threads:[~2024-05-28 15:14 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
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 [this message]
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