On Wed, 19 Jun 2024 13:58:44 +0200 Gerd Bayer <gbayer@xxxxxxxxxxxxx> wrote: > Hi all, > > this all started with a single patch by Ben to enable writing a user-mode > driver for a PCI device that requires 64bit register read/writes on s390. > A quick grep showed that there are several other drivers for PCI devices > in the kernel that use readq/writeq and eventually could use this, too. > So we decided to propose this for general inclusion. > > A couple of suggestions for refactorizations by Jason Gunthorpe and Alex > Williamson later [1], I arrived at this little series that avoids some > code duplication in vfio_pci_core_do_io_rw(). > Also, I've added a small patch to correct the spelling in one of the > declaration macros that was suggested by Ramesh Thomas [2]. However, > after some discussions about making 8-byte accesses available for x86, > Ramesh and I decided to do this in a separate patch [3]. > > This version was tested with a pass-through PCI device in a KVM guest > and with explicit test reads of size 8, 16, 32, and 64 bit on s390. > For 32bit architectures this has only been compile tested for the > 32bit ARM architecture. > > Thank you, > Gerd Bayer > > > [1] https://lore.kernel.org/all/20240422153508.2355844-1-gbayer@xxxxxxxxxxxxx/ > [2] https://lore.kernel.org/kvm/20240425165604.899447-1-gbayer@xxxxxxxxxxxxx/T/#m1b51fe155c60d04313695fbee11a2ccea856a98c > [3] https://lore.kernel.org/all/20240522232125.548643-1-ramesh.thomas@xxxxxxxxx/ > > Changes v5 -> v6: > - restrict patch 3/3 to just the typo fix - no move of semicolons Applied to vfio next branch for v6.11. Thanks, Alex > > Changes v4 -> v5: > - Make 8-byte accessors depend on the definitions of ioread64 and > iowrite64, again. Ramesh agreed to sort these out for x86 separately. > > Changes v3 -> v4: > - Make 64-bit accessors depend on CONFIG_64BIT (for x86, too). > - Drop conversion of if-else if chain to switch-case. > - Add patch to fix spelling of declaration macro. > > Changes v2 -> v3: > - Introduce macro to generate body of different-size accesses in > vfio_pci_core_do_io_rw (courtesy Alex Williamson). > - Convert if-else if chain to a switch-case construct to better > accommodate conditional compiles. > > Changes v1 -> v2: > - On non 64bit architecture use at most 32bit accesses in > vfio_pci_core_do_io_rw and describe that in the commit message. > - Drop the run-time error on 32bit architectures. > - The #endif splitting the "else if" is not really fortunate, but I'm > open to suggestions. > > > Ben Segal (1): > vfio/pci: Support 8-byte PCI loads and stores > > Gerd Bayer (2): > vfio/pci: Extract duplicated code into macro > vfio/pci: Fix typo in macro to declare accessors > > drivers/vfio/pci/vfio_pci_rdwr.c | 122 ++++++++++++++++--------------- > include/linux/vfio_pci_core.h | 21 +++--- > 2 files changed, 74 insertions(+), 69 deletions(-) >
