Attachment 281261 Details for Bug 245574 – Fix for the USB tablet from upstream

[patch] Fix for the USB tablet from upstream

xen-3.1.2-usb-tablet-fix.patch (text/plain), 3.33 KB, created by Chris Lalancette on 2007-12-07 14:58:45 UTC

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Creator: Chris Lalancette

Created: 2007-12-07 14:58:45 UTC

Size: 3.33 KB

patch

obsolete

>diff -urp xen-3.1.0-src.orig/tools/ioemu/target-i386-dm/exec-dm.c xen-3.1.0-src/tools/ioemu/target-i386-dm/exec-dm.c
>--- xen-3.1.0-src.orig/tools/ioemu/target-i386-dm/exec-dm.c	2007-05-18 10:45:21.000000000 -0400
>+++ xen-3.1.0-src/tools/ioemu/target-i386-dm/exec-dm.c	2007-12-07 09:36:39.000000000 -0500
>@@ -434,6 +434,68 @@ int iomem_index(target_phys_addr_t addr)
> extern unsigned long *logdirty_bitmap;
> extern unsigned long logdirty_bitmap_size;
> 
>+/*
>+ * Replace the standard byte memcpy with a word memcpy for appropriately sized
>+ * memory copy operations.  Some users (USB-UHCI) can not tolerate the possible
>+ * word tearing that can result from a guest concurrently writing a memory
>+ * structure while the qemu device model is modifying the same location.
>+ * Forcing a word-sized read/write prevents the guest from seeing a partially
>+ * written word-sized atom.
>+ */
>+#if defined(__x86_64__) || defined(__i386__)
>+static void memcpy_words(void *dst, void *src, size_t n)
>+{
>+    asm volatile (
>+        "   movl %%edx,%%ecx \n"
>+#ifdef __x86_64__
>+        "   shrl $3,%%ecx    \n"
>+        "   rep  movsq       \n"
>+        "   test $4,%%edx    \n"
>+        "   jz   1f          \n"
>+        "   movsl            \n"
>+#else /* __i386__ */
>+        "   shrl $2,%%ecx    \n"
>+        "   rep  movsl       \n"
>+#endif
>+        "1: test $2,%%edx    \n"
>+        "   jz   1f          \n"
>+        "   movsw            \n"
>+        "1: test $1,%%edx    \n"
>+        "   jz   1f          \n"
>+        "   movsb            \n"
>+        "1:                  \n"
>+        : "+S" (src), "+D" (dst) : "d" (n) : "ecx", "memory" );
>+}
>+#else
>+static void memcpy_words(void *dst, void *src, size_t n)
>+{
>+    /* Some architectures do not like unaligned accesses. */
>+    if (((unsigned long)dst | (unsigned long)src) & 3) {
>+        memcpy(dst, src, n);
>+        return;
>+    }
>+
>+    while (n >= sizeof(uint32_t)) {
>+        *((uint32_t *)dst) = *((uint32_t *)src);
>+        dst = ((uint32_t *)dst) + 1;
>+        src = ((uint32_t *)src) + 1;
>+        n -= sizeof(uint32_t);
>+    }
>+
>+    if (n & 2) {
>+        *((uint16_t *)dst) = *((uint16_t *)src);
>+        dst = ((uint16_t *)dst) + 1;
>+        src = ((uint16_t *)src) + 1;
>+    }
>+
>+    if (n & 1) {
>+        *((uint8_t *)dst) = *((uint8_t *)src);
>+        dst = ((uint8_t *)dst) + 1;
>+        src = ((uint8_t *)src) + 1;
>+    }
>+}
>+#endif
>+
> void cpu_physical_memory_rw(target_phys_addr_t addr, uint8_t *buf, 
>                             int len, int is_write)
> {
>@@ -470,7 +532,7 @@ void cpu_physical_memory_rw(target_phys_
>                 }
>             } else if ((ptr = phys_ram_addr(addr)) != NULL) {
>                 /* Writing to RAM */
>-                memcpy(ptr, buf, l);
>+                memcpy_words(ptr, buf, l);
>                 if (logdirty_bitmap != NULL) {
>                     /* Record that we have dirtied this frame */
>                     unsigned long pfn = addr >> TARGET_PAGE_BITS;
>@@ -506,7 +568,7 @@ void cpu_physical_memory_rw(target_phys_
>                 }
>             } else if ((ptr = phys_ram_addr(addr)) != NULL) {
>                 /* Reading from RAM */
>-                memcpy(buf, ptr, l);
>+                memcpy_words(buf, ptr, l);
>             } else {
>                 /* Neither RAM nor known MMIO space */
>                 memset(buf, 0xff, len); 
>Only in xen-3.1.0-src/tools/ioemu/target-i386-dm: exec-dm.c.orig

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Attachments on bug 245574: 281261