Hi Markus, On 7/13/21 10:46 PM, Markus Armbruster wrote: > Dongli Zhang <dongli.zh...@oracle.com> writes: > >> This patch is to add the HMP interface to dump MSI-X table and PBA, in >> order to help diagnose the loss of IRQ issue in VM (e.g., if an MSI-X >> vector is erroneously masked permanently). Here is the example with >> vhost-scsi: >> >> (qemu) info msix /machine/peripheral/vscsi0 >> Msg L.Addr Msg U.Addr Msg Data Vect Ctrl >> 0xfee00000 0x00000000 0x00004041 0x00000000 >> 0xfee00000 0x00000000 0x00004051 0x00000000 >> 0xfee00000 0x00000000 0x00004061 0x00000000 >> 0xfee00000 0x00000000 0x00004071 0x00000000 >> 0xfee01000 0x00000000 0x000040b1 0x00000000 >> 0xfee02000 0x00000000 0x000040c1 0x00000000 >> 0xfee03000 0x00000000 0x000040d1 0x00000000 >> >> MSI-X PBA >> 0 0 0 0 0 0 0 >> >> Since the number of MSI-X entries is not determined and might be very >> large, it is sometimes inappropriate to dump via QMP. > > Why? What makes HMP different?
Here are two reasons. 1. The size of MSI-X table is nondeterministic and might be very large, e.g., the PCI_MSIX_FLAGS_QSIZE is 0x07FF. The "info tlb" (which is a table and similar to MSI-X) and "info lapic" also only support hmp. 2. The [PATCH 3/3] of this patchset support device specific data, the definitional of which varies depending on each device type (so far only virtio-pci supports the interface). Thank you very much! Dongli Zhang > >> Therefore, this patch dumps MSI-X information only via HMP, which is >> similar to the implementation of hmp_info_mem(). >> >> Cc: Jason Wang <jasow...@redhat.com> >> Cc: Joe Jin <joe....@oracle.com> >> Signed-off-by: Dongli Zhang <dongli.zh...@oracle.com> >> Acked-by: Dr. David Alan Gilbert <dgilb...@redhat.com> >> Acked-by: Jason Wang <jasow...@redhat.com> >
