Merge tag 'pull-vfio-20250729' of https://github.com/legoater/qemu into staging

vfio queue:

* Fixed regression introduced by the `use-legacy-x86-rom` property
* Fixed regressions on IGD passthrough in legacy mode
* Fixed region mappings of sub-page BARs after CPR
* Removed build of SEV on 32-bit hosts

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# gpg: Good signature from "Cédric Le Goater <clg@redhat.com>" [full]
# gpg:                 aka "Cédric Le Goater <clg@kaod.org>" [full]
# Primary key fingerprint: A0F6 6548 F048 95EB FE6B  0B60 51A3 43C7 CFFB ECA1

* tag 'pull-vfio-20250729' of https://github.com/legoater/qemu:
  vfio/igd: Fix VGA regions are not exposed in legacy mode
  vfio/igd: Require host VGA decode for legacy mode
  vfio: fix sub-page bar after cpr
  i386: Build SEV only for 64-bit target
  hw/i386: Fix 'use-legacy-x86-rom' property compatibility

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

11 files changed, 48 insertions, 17 deletions

diff --git a/docs/igd-assign.txt b/docs/igd-assign.txt
index af4e8391fc..e54040335b 100644
--- a/docs/igd-assign.txt
+++ b/docs/igd-assign.txt
@@ -48,6 +48,7 @@ Intel document [1] shows how to dump VBIOS to file. For UEFI Option ROM, see
 QEMU also provides a "Legacy" mode that implicitly enables full functionality
 on IGD, it is automatically enabled when
 * IGD generation is 6 to 9 (Sandy Bridge to Comet Lake)
+* IGD claims VGA cycles on host (IGD is VGA controller on host)
 * Machine type is i440fx
 * IGD is assigned to guest BDF 00:02.0
 * ROM BAR or romfile is present
diff --git a/hw/core/machine.c b/hw/core/machine.c
index d6b2240fc2..bd47527479 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -41,7 +41,7 @@ GlobalProperty hw_compat_10_0[] = {
     { "scsi-hd", "dpofua", "off" },
     { "vfio-pci", "x-migration-load-config-after-iter", "off" },
     { "ramfb", "use-legacy-x86-rom", "true"},
-    { "vfio-pci", "use-legacy-x86-rom", "true" },
+    { "vfio-pci-nohotplug", "use-legacy-x86-rom", "true" },
 };
 const size_t hw_compat_10_0_len = G_N_ELEMENTS(hw_compat_10_0);
 
diff --git a/hw/i386/Kconfig b/hw/i386/Kconfig
index 14d23e27b5..5139d23087 100644
--- a/hw/i386/Kconfig
+++ b/hw/i386/Kconfig
@@ -4,7 +4,7 @@ config X86_FW_OVMF
 config SEV
     bool
     select X86_FW_OVMF
-    depends on KVM
+    depends on KVM && X86_64
 
 config SGX
     bool
diff --git a/hw/i386/microvm.c b/hw/i386/microvm.c
index d90b69a162..94d22a232a 100644
--- a/hw/i386/microvm.c
+++ b/hw/i386/microvm.c
@@ -635,7 +635,7 @@ GlobalProperty microvm_properties[] = {
      */
     { "pcie-root-port", "io-reserve", "0" },
     { TYPE_RAMFB_DEVICE, "use-legacy-x86-rom", "true" },
-    { TYPE_VFIO_PCI, "use-legacy-x86-rom", "true" },
+    { TYPE_VFIO_PCI_NOHOTPLUG, "use-legacy-x86-rom", "true" },
 };
 
 static void microvm_class_init(ObjectClass *oc, const void *data)
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index ad5caff3a5..c03324281b 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -80,7 +80,7 @@ static const int ide_irq[MAX_IDE_BUS] = { 14, 15 };
 
 static GlobalProperty pc_piix_compat_defaults[] = {
     { TYPE_RAMFB_DEVICE, "use-legacy-x86-rom", "true" },
-    { TYPE_VFIO_PCI, "use-legacy-x86-rom", "true" },
+    { TYPE_VFIO_PCI_NOHOTPLUG, "use-legacy-x86-rom", "true" },
 };
 static const size_t pc_piix_compat_defaults_len =
     G_N_ELEMENTS(pc_piix_compat_defaults);
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 9b9519fa02..b309b2b378 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -69,7 +69,7 @@
 static GlobalProperty pc_q35_compat_defaults[] = {
     { TYPE_VIRTIO_IOMMU_PCI, "aw-bits", "39" },
     { TYPE_RAMFB_DEVICE, "use-legacy-x86-rom", "true" },
-    { TYPE_VFIO_PCI, "use-legacy-x86-rom", "true" },
+    { TYPE_VFIO_PCI_NOHOTPLUG, "use-legacy-x86-rom", "true" },
 };
 static const size_t pc_q35_compat_defaults_len =
     G_N_ELEMENTS(pc_q35_compat_defaults);
diff --git a/hw/vfio/cpr.c b/hw/vfio/cpr.c
index af0f12a7ad..384b56c4c7 100644
--- a/hw/vfio/cpr.c
+++ b/hw/vfio/cpr.c
@@ -116,6 +116,8 @@ static int vfio_cpr_pci_post_load(void *opaque, int version_id)
     PCIDevice *pdev = &vdev->pdev;
     int nr_vectors;
 
+    vfio_sub_page_bar_update_mappings(vdev);
+
     if (msix_enabled(pdev)) {
         vfio_pci_msix_set_notifiers(vdev);
         nr_vectors = vdev->msix->entries;
diff --git a/hw/vfio/igd.c b/hw/vfio/igd.c
index e7a9d1ffc1..ee0767b0b8 100644
--- a/hw/vfio/igd.c
+++ b/hw/vfio/igd.c
@@ -113,6 +113,7 @@ static int igd_gen(VFIOPCIDevice *vdev)
 #define IGD_BDSM 0x5c /* Base Data of Stolen Memory */
 #define IGD_BDSM_GEN11 0xc0 /* Base Data of Stolen Memory of gen 11 and later */
 
+#define IGD_GMCH_VGA_DISABLE        BIT(1)
 #define IGD_GMCH_GEN6_GMS_SHIFT     3       /* SNB_GMCH in i915 */
 #define IGD_GMCH_GEN6_GMS_MASK      0x1f
 #define IGD_GMCH_GEN8_GMS_SHIFT     8       /* BDW_GMCH in i915 */
@@ -533,12 +534,14 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
     /*
      * For backward compatibility, enable legacy mode when
      * - Device geneation is 6 to 9 (including both)
+     * - IGD claims VGA cycles on host
      * - Machine type is i440fx (pc_piix)
      * - IGD device is at guest BDF 00:02.0
      * - Not manually disabled by x-igd-legacy-mode=off
      */
     if ((vdev->igd_legacy_mode != ON_OFF_AUTO_OFF) &&
         (gen >= 6 && gen <= 9) &&
+        !(gmch & IGD_GMCH_VGA_DISABLE) &&
         !strcmp(MACHINE_GET_CLASS(qdev_get_machine())->family, "pc_piix") &&
         (&vdev->pdev == pci_find_device(pci_device_root_bus(&vdev->pdev),
         0, PCI_DEVFN(0x2, 0)))) {
@@ -568,14 +571,16 @@ static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
         }
 
         /*
-         * If IGD VGA Disable is clear (expected) and VGA is not already
-         * enabled, try to enable it. Probably shouldn't be using legacy mode
-         * without VGA, but also no point in us enabling VGA if disabled in
-         * hardware.
+         * If VGA is not already enabled, try to enable it. We shouldn't be
+         * using legacy mode without VGA.
          */
-        if (!(gmch & 0x2) && !vdev->vga && !vfio_populate_vga(vdev, &err)) {
-            error_setg(&err, "Unable to enable VGA access");
-            goto error;
+        if (!vdev->vga) {
+            if (vfio_populate_vga(vdev, &err)) {
+                vfio_pci_config_register_vga(vdev);
+            } else {
+                error_setg(&err, "Unable to enable VGA access");
+                goto error;
+            }
         }
 
         /* Enable OpRegion and LPC bridge quirk */
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index e72d514a4c..4fa692c1a3 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -49,8 +49,6 @@
 #include "vfio-migration-internal.h"
 #include "vfio-helpers.h"
 
-#define TYPE_VFIO_PCI_NOHOTPLUG "vfio-pci-nohotplug"
-
 /* Protected by BQL */
 static KVMRouteChange vfio_route_change;
 
@@ -2826,6 +2824,20 @@ static int vfio_pci_load_config(VFIODevice *vbasedev, QEMUFile *f)
     return ret;
 }
 
+void vfio_sub_page_bar_update_mappings(VFIOPCIDevice *vdev)
+{
+    PCIDevice *pdev = &vdev->pdev;
+    int page_size = qemu_real_host_page_size();
+    int bar;
+
+    for (bar = 0; bar < PCI_ROM_SLOT; bar++) {
+        PCIIORegion *r = &pdev->io_regions[bar];
+        if (r->addr != PCI_BAR_UNMAPPED && r->size > 0 && r->size < page_size) {
+            vfio_sub_page_bar_update_mapping(pdev, bar);
+        }
+    }
+}
+
 static VFIODeviceOps vfio_pci_ops = {
     .vfio_compute_needs_reset = vfio_pci_compute_needs_reset,
     .vfio_hot_reset_multi = vfio_pci_hot_reset_multi,
@@ -3150,6 +3162,15 @@ static void vfio_unregister_req_notifier(VFIOPCIDevice *vdev)
     vdev->req_enabled = false;
 }
 
+void vfio_pci_config_register_vga(VFIOPCIDevice *vdev)
+{
+    assert(vdev->vga != NULL);
+
+    pci_register_vga(&vdev->pdev, &vdev->vga->region[QEMU_PCI_VGA_MEM].mem,
+                     &vdev->vga->region[QEMU_PCI_VGA_IO_LO].mem,
+                     &vdev->vga->region[QEMU_PCI_VGA_IO_HI].mem);
+}
+
 bool vfio_pci_config_setup(VFIOPCIDevice *vdev, Error **errp)
 {
     PCIDevice *pdev = &vdev->pdev;
@@ -3271,9 +3292,7 @@ bool vfio_pci_config_setup(VFIOPCIDevice *vdev, Error **errp)
     vfio_bars_register(vdev);
 
     if (vdev->vga && vfio_is_vga(vdev)) {
-        pci_register_vga(&vdev->pdev, &vdev->vga->region[QEMU_PCI_VGA_MEM].mem,
-                         &vdev->vga->region[QEMU_PCI_VGA_IO_LO].mem,
-                         &vdev->vga->region[QEMU_PCI_VGA_IO_HI].mem);
+        vfio_pci_config_register_vga(vdev);
     }
 
     return true;
diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index 248e5c4b16..81465a8214 100644
--- a/hw/vfio/pci.h
+++ b/hw/vfio/pci.h
@@ -219,6 +219,7 @@ void vfio_pci_write_config(PCIDevice *pdev,
 uint64_t vfio_vga_read(void *opaque, hwaddr addr, unsigned size);
 void vfio_vga_write(void *opaque, hwaddr addr, uint64_t data, unsigned size);
 
+void vfio_sub_page_bar_update_mappings(VFIOPCIDevice *vdev);
 bool vfio_opt_rom_in_denylist(VFIOPCIDevice *vdev);
 bool vfio_config_quirk_setup(VFIOPCIDevice *vdev, Error **errp);
 void vfio_vga_quirk_setup(VFIOPCIDevice *vdev);
@@ -252,6 +253,7 @@ extern const VMStateDescription vfio_display_vmstate;
 
 void vfio_pci_bars_exit(VFIOPCIDevice *vdev);
 bool vfio_pci_add_capabilities(VFIOPCIDevice *vdev, Error **errp);
+void vfio_pci_config_register_vga(VFIOPCIDevice *vdev);
 bool vfio_pci_config_setup(VFIOPCIDevice *vdev, Error **errp);
 bool vfio_pci_interrupt_setup(VFIOPCIDevice *vdev, Error **errp);
 void vfio_pci_intx_eoi(VFIODevice *vbasedev);
diff --git a/hw/vfio/types.h b/hw/vfio/types.h
index fa20c29b9f..c19334ff25 100644
--- a/hw/vfio/types.h
+++ b/hw/vfio/types.h
@@ -18,4 +18,6 @@
 #define TYPE_VFIO_PCI "vfio-pci"
 /* TYPE_VFIO_PCI shares struct VFIOPCIDevice. */
 
+#define TYPE_VFIO_PCI_NOHOTPLUG "vfio-pci-nohotplug"
+
 #endif /* HW_VFIO_VFIO_TYPES_H */