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[Qemu-devel] [PULL v2 02/49] msix: make pba size math more uniform
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] [PULL v2 02/49] msix: make pba size math more uniform |
Date: |
Tue, 15 Jan 2019 15:04:00 -0500 |
From: Dongli Zhang <address@hidden>
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 <address@hidden>
Reviewed-by: Michael S. Tsirkin <address@hidden>
Signed-off-by: Michael S. Tsirkin <address@hidden>
---
hw/pci/msix.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/hw/pci/msix.c b/hw/pci/msix.c
index c7bdbeda9e..4e336416a7 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
--
MST
- [Qemu-devel] [PULL v2 00/49] pci, pc, virtio: fixes, features, Michael S. Tsirkin, 2019/01/15
- [Qemu-devel] [PULL v2 14/49] tests: acpi: squash sanitize_fadt_ptrs() into test_acpi_fadt_table(), Michael S. Tsirkin, 2019/01/15
- [Qemu-devel] [PULL v2 06/49] vhost-user: fix ioeventfd_enabled, Michael S. Tsirkin, 2019/01/15
- [Qemu-devel] [PULL v2 05/49] tests: vhost-user-test: initialize 'fd' in chr_read, Michael S. Tsirkin, 2019/01/15