Misc patches for 8.2-rc0

[PULL 03/12] s390x/pci: only limit DMA aperture if vfio DMA limit reported

Thomas Huth posted 12 patches 1 year ago

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Maintainers: "Alex Bennée" <alex.bennee@linaro.org>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Thomas Huth <thuth@redhat.com>, Wainer dos Santos Moschetta <wainersm@redhat.com>, Beraldo Leal <bleal@redhat.com>, Gerd Hoffmann <kraxel@redhat.com>, Matthew Rosato <mjrosato@linux.ibm.com>, Eric Farman <farman@linux.ibm.com>, Richard Henderson <richard.henderson@linaro.org>, David Hildenbrand <david@redhat.com>, Ilya Leoshkevich <iii@linux.ibm.com>, Halil Pasic <pasic@linux.ibm.com>, Christian Borntraeger <borntraeger@linux.ibm.com>, Warner Losh <imp@bsdimp.com>, Kyle Evans <kevans@freebsd.org>

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[PULL 03/12] s390x/pci: only limit DMA aperture if vfio DMA limit reported

Posted by Thomas Huth 1 year ago

From: Matthew Rosato <mjrosato@linux.ibm.com>

If the host kernel lacks vfio DMA limit reporting, do not attempt
to shrink the guest DMA aperture.

Fixes: df202e3ff3 ("s390x/pci: shrink DMA aperture to be bound by vfio DMA limit")
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Message-ID: <20231110175108.465851-3-mjrosato@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 hw/s390x/s390-pci-vfio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/s390x/s390-pci-vfio.c b/hw/s390x/s390-pci-vfio.c
index e28573b593..7dbbc76823 100644
--- a/hw/s390x/s390-pci-vfio.c
+++ b/hw/s390x/s390-pci-vfio.c
@@ -136,7 +136,7 @@ static void s390_pci_read_base(S390PCIBusDevice *pbdev,
      * to the guest based upon the vfio DMA limit.
      */
     vfio_size = pbdev->iommu->max_dma_limit << TARGET_PAGE_BITS;
-    if (vfio_size < (cap->end_dma - cap->start_dma + 1)) {
+    if (vfio_size > 0 && vfio_size < cap->end_dma - cap->start_dma + 1) {
         pbdev->zpci_fn.edma = cap->start_dma + vfio_size - 1;
     }
 }
-- 
2.41.0