On 6/4/2024 4:46 AM, Gerd Bayer wrote:
Hi Ramesh, hi Jason,
being back from a short vacation, I think I'm sold on enabling x86 for
the 64bit accessors in vfio/pci.
On Tue, 2024-05-28 at 15:48 -0700, Ramesh Thomas wrote:
Hi Jason,
On 5/24/2024 7:00 AM, Jason Gunthorpe wrote:
On Wed, May 22, 2024 at 04:21:25PM -0700, Ramesh Thomas wrote:
ioread64 and iowrite64 macros called by vfio pci implementations
are
defined in asm/io.h if CONFIG_GENERIC_IOMAP is not defined.
Include
linux/io-64-nonatomic-lo-hi.h to define iowrite64 and ioread64
macros
when they are not defined. io-64-nonatomic-lo-hi.h maps the
macros to
generic implementation in lib/iomap.c. The generic implementation
does 64 bit rw if readq/writeq is defined for the architecture,
otherwise it would do 32 bit back to back rw.
Note that there are two versions of the generic implementation
that
differs in the order the 32 bit words are written if 64 bit
support is
not present. This is not the little/big endian ordering, which is
handled separately. This patch uses the lo followed by hi word
ordering
which is consistent with current back to back implementation in
the
vfio/pci code.
Refer patch series the requirement originated from:
https://lore.kernel.org/all/20240522150651.1999584-1-gbayer@xxxxxxxxxxxxx/
Signed-off-by: Ramesh Thomas <ramesh.thomas@xxxxxxxxx>
---
drivers/vfio/pci/vfio_pci_priv.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/vfio/pci/vfio_pci_priv.h
b/drivers/vfio/pci/vfio_pci_priv.h
index 5e4fa69aee16..5eab5abf2ff2 100644
--- a/drivers/vfio/pci/vfio_pci_priv.h
+++ b/drivers/vfio/pci/vfio_pci_priv.h
@@ -3,6 +3,7 @@
#define VFIO_PCI_PRIV_H
#include <linux/vfio_pci_core.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
Why include it here though?
It should go in vfio_pci_rdwr.c and this patch should remove all
the "#ifdef iowrite64"'s from that file too.
I was trying to make it future proof, but I agree it should be
included only where iowrite64/ioread64 is getting called. I will make
both the changes.
Thanks,
Ramesh
But the idea looks right to me
Thanks,
Jason
So how should we go about this?
To keep the scope that I can test manageable, my proposal would be:
I'll post a v5 of my series with the conditional compiles for
"ioread64"/"iowrite64" (effectively still excluding x86) - and you
Ramesh run this patch (add the include + change #ifdef's) as an
explicit patch on top?
Hi Gerd,
Sounds good. Meanwhile I am also trying to get this tested in x86.
Thanks,
Ramesh
Thanks,
Gerd
