search for: c7070619f340

This reverts commit c7070619f3408d9a0dffbed9149e6f00479cf43b. This has been shown to regress on some ARM systems: by forcing on DMA API usage for ARM systems, we have inadvertently kicked open a hornets' nest in terms of cache-coherency. Namely that unless the virtio device is explicitly described as capable of coherent DMA...

This reverts commit c7070619f3408d9a0dffbed9149e6f00479cf43b. This has been shown to regress on some ARM systems: by forcing on DMA API usage for ARM systems, we have inadvertently kicked open a hornets' nest in terms of cache-coherency. Namely that unless the virtio device is explicitly described as capable of coherent DMA...

...t affect devices setting the VIRTIO_F_IOMMU_PLATFORM flag, which as before are still at the mercy of architecture code correctly knowing their coherency, so explicitly call this out in the virtio-mmio DT binding in the hope of heading off any further workarounds for future firmware mishaps. Fixes: c7070619f340 ("vring: Force use of DMA API for ARM-based systems with legacy devices") Signed-off-by: Robin Murphy <robin.murphy at arm.com> --- Documentation/devicetree/bindings/virtio/mmio.txt | 3 +++ drivers/virtio/virtio_ring.c | 11 ++++++++--- 2 files changed, 11 in...

...t affect devices setting the VIRTIO_F_IOMMU_PLATFORM flag, which as before are still at the mercy of architecture code correctly knowing their coherency, so explicitly call this out in the virtio-mmio DT binding in the hope of heading off any further workarounds for future firmware mishaps. Fixes: c7070619f340 ("vring: Force use of DMA API for ARM-based systems with legacy devices") Signed-off-by: Robin Murphy <robin.murphy at arm.com> --- Documentation/devicetree/bindings/virtio/mmio.txt | 3 +++ drivers/virtio/virtio_ring.c | 11 ++++++++--- 2 files changed, 11 in...

...IRTIO_F_IOMMU_PLATFORM flag, > which as before are still at the mercy of architecture code correctly > knowing their coherency, so explicitly call this out in the virtio-mmio > DT binding in the hope of heading off any further workarounds for future > firmware mishaps. > > Fixes: c7070619f340 ("vring: Force use of DMA API for ARM-based systems with legacy devices") > Signed-off-by: Robin Murphy <robin.murphy at arm.com> > --- > Documentation/devicetree/bindings/virtio/mmio.txt | 3 +++ > drivers/virtio/virtio_ring.c | 11 ++++++++--- &gt...

...IRTIO_F_IOMMU_PLATFORM flag, > which as before are still at the mercy of architecture code correctly > knowing their coherency, so explicitly call this out in the virtio-mmio > DT binding in the hope of heading off any further workarounds for future > firmware mishaps. > > Fixes: c7070619f340 ("vring: Force use of DMA API for ARM-based systems with legacy devices") > Signed-off-by: Robin Murphy <robin.murphy at arm.com> > --- > Documentation/devicetree/bindings/virtio/mmio.txt | 3 +++ > drivers/virtio/virtio_ring.c | 11 ++++++++--- &gt...

...iting a few characters as host data in cache and guest data directly in RAM go out of sync. In order to fix this, narrow the scope of the original workaround from all legacy devices to just those behind IOMMUs, which was really the only thing we were trying to deal with in the first place. Fixes: c7070619f340 ("vring: Force use of DMA API for ARM-based systems with legacy devices") Signed-off-by: Robin Murphy <robin.murphy at arm.com> --- drivers/virtio/virtio_ring.c | 30 ++++++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-) diff --git a/drivers/virtio/virtio...

...iting a few characters as host data in cache and guest data directly in RAM go out of sync. In order to fix this, narrow the scope of the original workaround from all legacy devices to just those behind IOMMUs, which was really the only thing we were trying to deal with in the first place. Fixes: c7070619f340 ("vring: Force use of DMA API for ARM-based systems with legacy devices") Signed-off-by: Robin Murphy <robin.murphy at arm.com> --- drivers/virtio/virtio_ring.c | 30 ++++++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-) diff --git a/drivers/virtio/virtio...