xen, gfx passthrough: add opregion mapping

The OpRegion shouldn't be mapped 1:1 because the address in the host
can't be used in the guest directly.

This patch traps read and write access to the opregion of the Intel
GPU config space (offset 0xfc).

The original patch is from Jean Guyader <jean.guyader@eu.citrix.com>

Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

1 files changed, 82 insertions, 0 deletions

diff --git a/hw/xen/xen_pt_graphics.c b/hw/xen/xen_pt_graphics.c
index 3232296bf8..df6069bf63 100644
--- a/hw/xen/xen_pt_graphics.c
+++ b/hw/xen/xen_pt_graphics.c
@@ -5,6 +5,11 @@
 #include "xen-host-pci-device.h"
 #include "hw/xen/xen_backend.h"
 
+static unsigned long igd_guest_opregion;
+static unsigned long igd_host_opregion;
+
+#define XEN_PCI_INTEL_OPREGION_MASK 0xfff
+
 typedef struct VGARegion {
     int type;           /* Memory or port I/O */
     uint64_t guest_base_addr;
@@ -81,6 +86,7 @@ int xen_pt_register_vga_regions(XenHostPCIDevice *dev)
 int xen_pt_unregister_vga_regions(XenHostPCIDevice *dev)
 {
     int i = 0;
+    int ret = 0;
 
     if (!is_igd_vga_passthrough(dev)) {
         return 0;
@@ -107,6 +113,17 @@ int xen_pt_unregister_vga_regions(XenHostPCIDevice *dev)
         }
     }
 
+    if (igd_guest_opregion) {
+        ret = xc_domain_memory_mapping(xen_xc, xen_domid,
+                (unsigned long)(igd_guest_opregion >> XC_PAGE_SHIFT),
+                (unsigned long)(igd_host_opregion >> XC_PAGE_SHIFT),
+                3,
+                DPCI_REMOVE_MAPPING);
+        if (ret) {
+            return ret;
+        }
+    }
+
     return 0;
 }
 
@@ -188,3 +205,68 @@ int xen_pt_setup_vga(XenPCIPassthroughState *s, XenHostPCIDevice *dev)
     cpu_physical_memory_rw(0xc0000, bios, bios_size, 1);
     return 0;
 }
+
+uint32_t igd_read_opregion(XenPCIPassthroughState *s)
+{
+    uint32_t val = 0;
+
+    if (!igd_guest_opregion) {
+        return val;
+    }
+
+    val = igd_guest_opregion;
+
+    XEN_PT_LOG(&s->dev, "Read opregion val=%x\n", val);
+    return val;
+}
+
+#define XEN_PCI_INTEL_OPREGION_PAGES 0x3
+#define XEN_PCI_INTEL_OPREGION_ENABLE_ACCESSED 0x1
+void igd_write_opregion(XenPCIPassthroughState *s, uint32_t val)
+{
+    int ret;
+
+    if (igd_guest_opregion) {
+        XEN_PT_LOG(&s->dev, "opregion register already been set, ignoring %x\n",
+                   val);
+        return;
+    }
+
+    /* We just work with LE. */
+    xen_host_pci_get_block(&s->real_device, XEN_PCI_INTEL_OPREGION,
+            (uint8_t *)&igd_host_opregion, 4);
+    igd_guest_opregion = (unsigned long)(val & ~XEN_PCI_INTEL_OPREGION_MASK)
+                            | (igd_host_opregion & XEN_PCI_INTEL_OPREGION_MASK);
+
+    ret = xc_domain_iomem_permission(xen_xc, xen_domid,
+            (unsigned long)(igd_host_opregion >> XC_PAGE_SHIFT),
+            XEN_PCI_INTEL_OPREGION_PAGES,
+            XEN_PCI_INTEL_OPREGION_ENABLE_ACCESSED);
+
+    if (ret) {
+        XEN_PT_ERR(&s->dev, "[%d]:Can't enable to access IGD host opregion:"
+                    " 0x%lx.\n", ret,
+                    (unsigned long)(igd_host_opregion >> XC_PAGE_SHIFT)),
+        igd_guest_opregion = 0;
+        return;
+    }
+
+    ret = xc_domain_memory_mapping(xen_xc, xen_domid,
+            (unsigned long)(igd_guest_opregion >> XC_PAGE_SHIFT),
+            (unsigned long)(igd_host_opregion >> XC_PAGE_SHIFT),
+            XEN_PCI_INTEL_OPREGION_PAGES,
+            DPCI_ADD_MAPPING);
+
+    if (ret) {
+        XEN_PT_ERR(&s->dev, "[%d]:Can't map IGD host opregion:0x%lx to"
+                    " guest opregion:0x%lx.\n", ret,
+                    (unsigned long)(igd_host_opregion >> XC_PAGE_SHIFT),
+                    (unsigned long)(igd_guest_opregion >> XC_PAGE_SHIFT));
+        igd_guest_opregion = 0;
+        return;
+    }
+
+    XEN_PT_LOG(&s->dev, "Map OpRegion: 0x%lx -> 0x%lx\n",
+                    (unsigned long)(igd_host_opregion >> XC_PAGE_SHIFT),
+                    (unsigned long)(igd_guest_opregion >> XC_PAGE_SHIFT));
+}