From 44ed44aefec571041fe3b3a8b6849613a74b520a Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Sat, 18 Jan 2025 03:28:40 +1000 Subject: [PATCH] hw/pci/msix: Warn on PBA writes MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Of the MSI-X PBA pending bits, the PCI Local Bus Specification says: Software should never write, and should only read Pending Bits. If software writes to Pending Bits, the result is undefined. Log a GUEST_ERROR message if the PBA is written to by software. Cc: Marcel Apfelbaum Cc: Dmitry Fleytman Cc: Sriram Yagnaraman Signed-off-by: Nicholas Piggin Message-Id: <20250117172842.406338-2-npiggin@gmail.com> Reviewed-by: Phil Dennis-Jordan Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Akihiko Odaki Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/pci/msix.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/hw/pci/msix.c b/hw/pci/msix.c index 57ec7084a4..66f27b9d71 100644 --- a/hw/pci/msix.c +++ b/hw/pci/msix.c @@ -15,6 +15,7 @@ */ #include "qemu/osdep.h" +#include "qemu/log.h" #include "hw/pci/msi.h" #include "hw/pci/msix.h" #include "hw/pci/pci.h" @@ -260,6 +261,14 @@ static uint64_t msix_pba_mmio_read(void *opaque, hwaddr addr, static void msix_pba_mmio_write(void *opaque, hwaddr addr, uint64_t val, unsigned size) { + PCIDevice *dev = opaque; + + qemu_log_mask(LOG_GUEST_ERROR, + "PCI [%s:%02x:%02x.%x] attempt to write to MSI-X " + "PBA at 0x%" FMT_PCIBUS ", ignoring.\n", + pci_root_bus_path(dev), pci_dev_bus_num(dev), + PCI_SLOT(dev->devfn), PCI_FUNC(dev->devfn), + addr); } static const MemoryRegionOps msix_pba_mmio_ops = { -- 2.30.2