virtio-iommu: Standardize granule extraction and formatting

At several locations we compute the granule from the config
page_size_mask using ctz() and then format it in traces using
BIT(). As the page_size_mask is 64b we should use ctz64 and
BIT_ULL() for formatting. We failed to be consistent.

Note the page_size_mask is garanteed to be non null. The spec
mandates the device to set at least one bit, so ctz64 cannot
return 64. This is garanteed by the fact the device
initializes the page_size_mask to qemu_target_page_mask()
and then the page_size_mask is further constrained by
virtio_iommu_set_page_size_mask() callback which can't
result in a new mask being null. So if Coverity complains
round those ctz64/BIT_ULL with CID 1517772 this is a false
positive

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Fixes: 94df5b2180 ("virtio-iommu: Fix 64kB host page size VFIO device assignment")
Message-Id: <20230718182136.40096-1-eric.auger@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>

diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
index 4dcf1d5c62f53a82eb7c0c49401d4e9497768a27..be51635895ce88cb69ec987a5c7d3fa33a703c9e 100644 (file)
--- a/hw/virtio/virtio-iommu.c
+++ b/hw/virtio/virtio-iommu.c
@@ -854,17 +854,19 @@ static IOMMUTLBEntry virtio_iommu_translate(IOMMUMemoryRegion *mr, hwaddr addr,
     VirtIOIOMMUEndpoint *ep;
     uint32_t sid, flags;
     bool bypass_allowed;
+    int granule;
     bool found;
     int i;
 
     interval.low = addr;
     interval.high = addr + 1;
+    granule = ctz64(s->config.page_size_mask);
 
     IOMMUTLBEntry entry = {
         .target_as = &address_space_memory,
         .iova = addr,
         .translated_addr = addr,
-        .addr_mask = (1 << ctz32(s->config.page_size_mask)) - 1,
+        .addr_mask = BIT_ULL(granule) - 1,
         .perm = IOMMU_NONE,
     };
 
@@ -1117,7 +1119,7 @@ static int virtio_iommu_set_page_size_mask(IOMMUMemoryRegion *mr,
     if (s->granule_frozen) {
         int cur_granule = ctz64(cur_mask);
 
-        if (!(BIT(cur_granule) & new_mask)) {
+        if (!(BIT_ULL(cur_granule) & new_mask)) {
             error_setg(errp, "virtio-iommu %s does not support frozen granule 0x%llx",
                        mr->parent_obj.name, BIT_ULL(cur_granule));
             return -1;
@@ -1163,7 +1165,7 @@ static void virtio_iommu_freeze_granule(Notifier *notifier, void *data)
     }
     s->granule_frozen = true;
     granule = ctz64(s->config.page_size_mask);
-    trace_virtio_iommu_freeze_granule(BIT(granule));
+    trace_virtio_iommu_freeze_granule(BIT_ULL(granule));
 }
 
 static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)