[PULL 1/3] xen/pt: Emulate multifunction bit in header type

[Anthony PERARD <anthony.perard@citrix.com>]

From: Ross Lagerwall <ross.lagerwall@citrix.com>

The intention of the code appears to have been to unconditionally set
the multifunction bit but since the emulation mask is 0x00 it has no
effect. Instead, emulate the bit and set it based on the multifunction
property of the PCIDevice (which can be set using QAPI).

This allows making passthrough devices appear as functions in a Xen
guest.

Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Message-Id: <20231103172601.1319375-1-ross.lagerwall@citrix.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
---
 hw/xen/xen_pt_config_init.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/hw/xen/xen_pt_config_init.c b/hw/xen/xen_pt_config_init.c
index ba4cd78238..3edaeab1e3 100644
--- a/hw/xen/xen_pt_config_init.c
+++ b/hw/xen/xen_pt_config_init.c
@@ -292,7 +292,10 @@ static int xen_pt_header_type_reg_init(XenPCIPassthroughState *s,
                                        uint32_t *data)
 {
     /* read PCI_HEADER_TYPE */
-    *data = reg->init_val | 0x80;
+    *data = reg->init_val;
+    if ((PCI_DEVICE(s)->cap_present & QEMU_PCI_CAP_MULTIFUNCTION)) {
+        *data |= PCI_HEADER_TYPE_MULTI_FUNCTION;
+    }
     return 0;
 }
 
@@ -677,7 +680,7 @@ static XenPTRegInfo xen_pt_emu_reg_header0[] = {
         .size       = 1,
         .init_val   = 0x00,
         .ro_mask    = 0xFF,
-        .emu_mask   = 0x00,
+        .emu_mask   = PCI_HEADER_TYPE_MULTI_FUNCTION,
         .init       = xen_pt_header_type_reg_init,
         .u.b.read   = xen_pt_byte_reg_read,
         .u.b.write  = xen_pt_byte_reg_write,
-- 
Anthony PERARD