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net: mana: Cap MSI-X vectors to the device MSI-X table size

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mana_gd_query_max_resources() sizes gc->num_msix_usable from resp.max_msix
and the CPU count, but never from the device MSI-X table. On a 1792 vCPU
M-series VM that yields 1793 while the table has 1024 entries, and
mana_gd_setup_remaining_irqs() then walks indices 1..1792, running off the
end of the region mapped by msix_map_region():

  BUG: unable to handle page fault for address: ff8e347f8b99800c
  RIP: 0010:msix_prepare_msi_desc+0x7a/0x90
  RAX: 0000000000004000 RBX: ff4330cb164ea780 RCX: ff8e347f8b998000
  Call Trace:
   <TASK>
   __msi_domain_alloc_irqs+0x13a/0x440
   msi_domain_alloc_irq_at+0x149/0x1b0
   mana_gd_setup+0x351/0x890
   mana_gd_probe+0x274/0x390
   </TASK>

RAX is index 1024 * PCI_MSIX_ENTRY_SIZE, one entry past the table.

msi_insert_desc() does range check the index, but only against the MSI
domain hwsize, which matches the table only for devices on an MSI parent
domain. With a global PCI/MSI domain hwsize is MSI_XA_DOMAIN_SIZE, so
nothing bounds the request.

Cap num_msix_usable with pci_msix_vec_count().

Fixes: 7553911210 ("net: mana: Allocate MSI-X vectors dynamically")
Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260821183736.733296-1-longli@microsoft.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Long Li 2026-08-21 11:37:36 -07:00 committed by Jakub Kicinski
parent 5b483f7791
commit 2c7493f980
1 changed files with 19 additions and 0 deletions
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19
drivers/net/ethernet/microsoft/mana/gdma_main.c
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@ -182,6 +182,7 @@ static int mana_gd_query_max_resources(struct pci_dev *pdev)
struct gdma_query_max_resources_resp resp = {};
struct gdma_general_req req = {};
unsigned int max_num_queues;
unsigned int msix_vec_count;
u8 bm_hostmode;
u16 num_ports;
int err;
@ -218,6 +219,24 @@ static int mana_gd_query_max_resources(struct pci_dev *pdev)
gc->num_msix_usable = min(resp.max_msix, num_online_cpus() + 1);
}
/* MSI-X vectors are allocated by index into the device MSI-X table, so
* never ask for more than the table holds. It can be smaller than both
* resp.max_msix and the CPU count.
*/
err = pci_msix_vec_count(pdev);
if (err <= 0) {
dev_err(gc->dev, "Failed to query MSI-X table size: %d\n", err);
return err < 0 ? err : -ENOSPC;
}
msix_vec_count = err;
if (gc->num_msix_usable > msix_vec_count) {
dev_info(gc->dev,
"Limiting MSI-X vectors from %u to table size %u\n",
gc->num_msix_usable, msix_vec_count);
gc->num_msix_usable = msix_vec_count;
}
if (gc->num_msix_usable <= 1)
return -ENOSPC;