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| author | Dongli Zhang <dongli.zhang@oracle.com> | 2018-12-17 07:34:39 +0800 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2019-01-14 19:31:04 -0500 |
| commit | 17323e8b689a1f6d1b711df034e9ee3a88ff27ba (patch) | |
| tree | 1a8873d5474b1d32afe630ba049e12c8e7d2905e /hw/pci/msix.c | |
| parent | b9731850d746e528d317097f907f27116798d7fe (diff) | |
| download | qemu-17323e8b689a1f6d1b711df034e9ee3a88ff27ba.zip qemu-17323e8b689a1f6d1b711df034e9ee3a88ff27ba.tar.gz qemu-17323e8b689a1f6d1b711df034e9ee3a88ff27ba.tar.bz2 | |
msix: make pba size math more uniform
In msix_exclusive_bar the bar_pba_size is more than what the pba is
expected to have, although this never affects the bar size.
Specifically, the math in msix_init_exclusive_bar allocates too much
memory in some cases.
For example consider nentries = 8. msix_exclusive_bar will give us
bar_pba_size = 16. So 16 bytes. However 8 bytes would be enough - this
is all that the spec requires.
So in practice bar_pba_size sometimes allocates an extra 8 bytes but
never more.
Since each MSIX entry size is 16 bytes, and since we make sure that
table+pba is a power of two, this always leaves a multiple of 16 bytes
for the PBA, so extra 8 bytes have no effect.
However, its ugly to have pba size temporary variable have an incorrect
value. For consistency switch to the formula used in msix_init.
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw/pci/msix.c')
| -rw-r--r-- | hw/pci/msix.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/hw/pci/msix.c b/hw/pci/msix.c index c7bdbed..4e33641 100644 --- a/hw/pci/msix.c +++ b/hw/pci/msix.c @@ -345,7 +345,7 @@ int msix_init_exclusive_bar(PCIDevice *dev, unsigned short nentries, char *name; uint32_t bar_size = 4096; uint32_t bar_pba_offset = bar_size / 2; - uint32_t bar_pba_size = (nentries / 8 + 1) * 8; + uint32_t bar_pba_size = QEMU_ALIGN_UP(nentries, 64) / 8; /* * Migration compatibility dictates that this remains a 4k |