diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 9436ac5cc9..cab2aecb80 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -1356,6 +1356,98 @@ static void vfio_pci_fixup_msix_region(VFIOPCIDevice *vdev)
}
}
+static void vfio_pci_relocate_msix(VFIOPCIDevice *vdev, Error **errp)
+{
+ int target_bar = -1;
+ size_t msix_sz;
+
+ if (!vdev->msix || vdev->msix_relo == OFF_AUTOPCIBAR_OFF) {
+ return;
+ }
+
+ /* The actual minimum size of MSI-X structures */
+ msix_sz = (vdev->msix->entries * PCI_MSIX_ENTRY_SIZE) +
+ (QEMU_ALIGN_UP(vdev->msix->entries, 64) / 8);
+ /* Round up to host pages, we don't want to share a page */
+ msix_sz = REAL_HOST_PAGE_ALIGN(msix_sz);
+ /* PCI BARs must be a power of 2 */
+ msix_sz = pow2ceil(msix_sz);
+
+ if (vdev->msix_relo == OFF_AUTOPCIBAR_AUTO) {
+ /*
+ * TODO: Lookup table for known devices.
+ *
+ * Logically we might use an algorithm here to select the BAR adding
+ * the least additional MMIO space, but we cannot programatically
+ * predict the driver dependency on BAR ordering or sizing, therefore
+ * 'auto' becomes a lookup for combinations reported to work.
+ */
+ if (target_bar < 0) {
+ error_setg(errp, "No automatic MSI-X relocation available for "
+ "device %04x:%04x", vdev->vendor_id, vdev->device_id);
+ return;
+ }
+ } else {
+ target_bar = (int)(vdev->msix_relo - OFF_AUTOPCIBAR_BAR0);
+ }
+
+ /* I/O port BARs cannot host MSI-X structures */
+ if (vdev->bars[target_bar].ioport) {
+ error_setg(errp, "Invalid MSI-X relocation BAR %d, "
+ "I/O port BAR", target_bar);
+ return;
+ }
+
+ /* Cannot use a BAR in the "shadow" of a 64-bit BAR */
+ if (!vdev->bars[target_bar].size &&
+ target_bar > 0 && vdev->bars[target_bar - 1].mem64) {
+ error_setg(errp, "Invalid MSI-X relocation BAR %d, "
+ "consumed by 64-bit BAR %d", target_bar, target_bar - 1);
+ return;
+ }
+
+ /* 2GB max size for 32-bit BARs, cannot double if already > 1G */
+ if (vdev->bars[target_bar].size > (1 * 1024 * 1024 * 1024) &&
+ !vdev->bars[target_bar].mem64) {
+ error_setg(errp, "Invalid MSI-X relocation BAR %d, "
+ "no space to extend 32-bit BAR", target_bar);
+ return;
+ }
+
+ /*
+ * If adding a new BAR, test if we can make it 64bit. We make it
+ * prefetchable since QEMU MSI-X emulation has no read side effects
+ * and doing so makes mapping more flexible.
+ */
+ if (!vdev->bars[target_bar].size) {
+ if (target_bar < (PCI_ROM_SLOT - 1) &&
+ !vdev->bars[target_bar + 1].size) {
+ vdev->bars[target_bar].mem64 = true;
+ vdev->bars[target_bar].type = PCI_BASE_ADDRESS_MEM_TYPE_64;
+ }
+ vdev->bars[target_bar].type |= PCI_BASE_ADDRESS_MEM_PREFETCH;
+ vdev->bars[target_bar].size = msix_sz;
+ vdev->msix->table_offset = 0;
+ } else {
+ vdev->bars[target_bar].size = MAX(vdev->bars[target_bar].size * 2,
+ msix_sz * 2);
+ /*
+ * Due to above size calc, MSI-X always starts halfway into the BAR,
+ * which will always be a separate host page.
+ */
+ vdev->msix->table_offset = vdev->bars[target_bar].size / 2;
+ }
+
+ vdev->msix->table_bar = target_bar;
+ vdev->msix->pba_bar = target_bar;
+ /* Requires 8-byte alignment, but PCI_MSIX_ENTRY_SIZE guarantees that */
+ vdev->msix->pba_offset = vdev->msix->table_offset +
+ (vdev->msix->entries * PCI_MSIX_ENTRY_SIZE);
+
+ trace_vfio_msix_relo(vdev->vbasedev.name,
+ vdev->msix->table_bar, vdev->msix->table_offset);
+}
+
/*
* We don't have any control over how pci_add_capability() inserts
* capabilities into the chain. In order to setup MSI-X we need a
@@ -1434,6 +1526,8 @@ static void vfio_msix_early_setup(VFIOPCIDevice *vdev, Error **errp)
vdev->msix = msix;
vfio_pci_fixup_msix_region(vdev);
+
+ vfio_pci_relocate_msix(vdev, errp);
}
static int vfio_msix_setup(VFIOPCIDevice *vdev, int pos, Error **errp)
@@ -2849,13 +2943,14 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
vfio_pci_size_rom(vdev);
+ vfio_bars_prepare(vdev);
+
vfio_msix_early_setup(vdev, &err);
if (err) {
error_propagate(errp, err);
goto error;
}
- vfio_bars_prepare(vdev);
vfio_bars_register(vdev);
ret = vfio_add_capabilities(vdev, errp);
@@ -3045,6 +3140,8 @@ static Property vfio_pci_dev_properties[] = {
DEFINE_PROP_UNSIGNED_NODEFAULT("x-nv-gpudirect-clique", VFIOPCIDevice,
nv_gpudirect_clique,
qdev_prop_nv_gpudirect_clique, uint8_t),
+ DEFINE_PROP_OFF_AUTO_PCIBAR("x-msix-relocation", VFIOPCIDevice, msix_relo,
+ OFF_AUTOPCIBAR_OFF),
/*
* TODO - support passed fds... is this necessary?
* DEFINE_PROP_STRING("vfiofd", VFIOPCIDevice, vfiofd_name),
diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index dcdb1a8067..588381f201 100644
--- a/hw/vfio/pci.h
+++ b/hw/vfio/pci.h
@@ -135,6 +135,7 @@ typedef struct VFIOPCIDevice {
(1 << VFIO_FEATURE_ENABLE_IGD_OPREGION_BIT)
int32_t bootindex;
uint32_t igd_gms;
+ OffAutoPCIBAR msix_relo;
uint8_t pm_cap;
uint8_t nv_gpudirect_clique;
bool pci_aer;
diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index 3d34fe8a93..79f63a2ff6 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -16,6 +16,8 @@ vfio_msix_pba_disable(const char *name) " (%s)"
vfio_msix_pba_enable(const char *name) " (%s)"
vfio_msix_disable(const char *name) " (%s)"
vfio_msix_fixup(const char *name, int bar, uint64_t start, uint64_t end) " (%s) MSI-X region %d mmap fixup [0x%"PRIx64" - 0x%"PRIx64"]"
+vfio_msix_relo_cost(const char *name, int bar, uint64_t cost) " (%s) BAR %d cost 0x%"PRIx64""
+vfio_msix_relo(const char *name, int bar, uint64_t offset) " (%s) BAR %d offset 0x%"PRIx64""
vfio_msi_enable(const char *name, int nr_vectors) " (%s) Enabled %d MSI vectors"
vfio_msi_disable(const char *name) " (%s)"
vfio_pci_load_rom(const char *name, unsigned long size, unsigned long offset, unsigned long flags) "Device %s ROM:\n size: 0x%lx, offset: 0x%lx, flags: 0x%lx"