vga: edid fixes, qxl clang workaround, vga mmio subregion fix.

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Merge remote-tracking branch 'remotes/kraxel/tags/vga-20181005-pull-request' into staging

vga: edid fixes, qxl clang workaround, vga mmio subregion fix.

# gpg: Signature made Fri 05 Oct 2018 12:11:40 BST
# gpg:                using RSA key 4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>"
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>"
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>"
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* remotes/kraxel/tags/vga-20181005-pull-request:
  edid: fix vendor default
  secondary-vga: delete mmio subregions upon exit
  hw/display/qxl: Suppress clang-7 warning about misaligned atomic operation
  edid: Ignore built binary

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

.gitignore

@@ -107,6 +107,7 @@
 /qemu-doc.html
 /qemu-doc.info
 /qemu-doc.txt
+/qemu-edid
 /qemu-img
 /qemu-nbd
 /qemu-options.def

hw/display/edid-generate.c

@@ -301,7 +301,7 @@ void qemu_edid_generate(uint8_t *edid, size_t size,
     /* =============== set defaults  =============== */
 
     if (!info->vendor || strlen(info->vendor) != 3) {
-        info->vendor = "EMU";
+        info->vendor = "RHT";
     }
     if (!info->name) {
         info->name = "QEMU Monitor";

hw/display/qxl.c

@@ -1893,7 +1893,31 @@ static void qxl_send_events(PCIQXLDevice *d, uint32_t events)
         trace_qxl_send_events_vm_stopped(d->id, events);
         return;
     }
-    old_pending = atomic_fetch_or(&d->ram->int_pending, le_events);
+    /*
+     * Older versions of Spice forgot to define the QXLRam struct
+     * with the '__aligned__(4)' attribute. clang 7 and newer will
+     * thus warn that atomic_fetch_or(&d->ram->int_pending, ...)
+     * might be a misaligned atomic access, and will generate an
+     * out-of-line call for it, which results in a link error since
+     * we don't currently link against libatomic.
+     *
+     * In fact we set up d->ram in init_qxl_ram() so it always starts
+     * at a 4K boundary, so we know that &d->ram->int_pending is
+     * naturally aligned for a uint32_t. Newer Spice versions
+     * (with Spice commit beda5ec7a6848be20c0cac2a9a8ef2a41e8069c1)
+     * will fix the bug directly. To deal with older versions,
+     * we tell the compiler to assume the address really is aligned.
+     * Any compiler which cares about the misalignment will have
+     * __builtin_assume_aligned.
+     */
+#ifdef HAS_ASSUME_ALIGNED
+#define ALIGNED_UINT32_PTR(P) ((uint32_t *)__builtin_assume_aligned(P, 4))
+#else
+#define ALIGNED_UINT32_PTR(P) ((uint32_t *)P)
+#endif
+
+    old_pending = atomic_fetch_or(ALIGNED_UINT32_PTR(&d->ram->int_pending),
+                                  le_events);
     if ((old_pending & le_events) == le_events) {
         return;
     }

hw/display/vga-pci.c

@@ -309,6 +309,14 @@ static void pci_secondary_vga_exit(PCIDevice *dev)
     VGACommonState *s = &d->vga;
 
     graphic_console_close(s->con);
+    memory_region_del_subregion(&d->mmio, &d->mrs[0]);
+    memory_region_del_subregion(&d->mmio, &d->mrs[1]);
+    if (d->flags & (1 << PCI_VGA_FLAG_ENABLE_QEXT)) {
+        memory_region_del_subregion(&d->mmio, &d->mrs[2]);
+    }
+    if (d->flags & (1 << PCI_VGA_FLAG_ENABLE_EDID)) {
+        memory_region_del_subregion(&d->mmio, &d->mrs[3]);
+    }
 }
 
 static void pci_secondary_vga_init(Object *obj)

include/hw/display/edid.h

@@ -4,7 +4,7 @@
 #include "hw/hw.h"
 
 typedef struct qemu_edid_info {
-    const char *vendor;
+    const char *vendor; /* http://www.uefi.org/pnp_id_list */
     const char *name;
     const char *serial;
     uint32_t    dpi;

include/qemu/compiler.h

@@ -122,6 +122,15 @@
 #ifndef __has_feature
 #define __has_feature(x) 0 /* compatibility with non-clang compilers */
 #endif
+
+#ifndef __has_builtin
+#define __has_builtin(x) 0 /* compatibility with non-clang compilers */
+#endif
+
+#if __has_builtin(__builtin_assume_aligned) || QEMU_GNUC_PREREQ(4, 7)
+#define HAS_ASSUME_ALIGNED
+#endif
+
 /* Implement C11 _Generic via GCC builtins.  Example:
  *
  *    QEMU_GENERIC(x, (float, sinf), (long double, sinl), sin) (x)