Hi,
> No, the test is for if the first (current) operation is crossing a
> page boundary, not if the NEXT one is... That's why the code in this
> condition is using hvm_copy to fetch the data that is being
> accessed...
Ok, point taken. But that also means that the access range calculation
isn't that simple, it's quite different for the two directions ...
Patch against 9681 (testing repository) attached.
cheers,
Gerd
--
Gerd Hoffmann <kraxel@xxxxxxx>
Erst mal heiraten, ein, zwei Kinder, und wenn alles läuft
geh' ich nach drei Jahren mit der Familie an die Börse.
http://www.suse.de/~kraxel/julika-dora.jpeg
diff -r 42eee0575ab7 xen/arch/x86/hvm/platform.c
--- a/xen/arch/x86/hvm/platform.c Tue May 16 18:52:53 2006
+++ b/xen/arch/x86/hvm/platform.c Thu May 18 14:09:36 2006
@@ -830,7 +830,7 @@
unsigned long count = GET_REPEAT_COUNT();
unsigned long size = mmio_inst.op_size;
int sign = regs->eflags & EF_DF ? -1 : 1;
- unsigned long addr = 0;
+ unsigned long addr, high_addr, low_addr;
int dir;
/* determine non-MMIO address */
@@ -851,6 +851,13 @@
addr = regs->edi;
}
}
+ if (sign > 0) {
+ high_addr = addr + count * size - 1;
+ low_addr = addr;
+ } else {
+ high_addr = addr + size - 1;
+ low_addr = addr - (count-1) * size;
+ }
mmio_opp->flags = mmio_inst.flags;
mmio_opp->instr = mmio_inst.instr;
@@ -865,7 +872,8 @@
* copy ourself. After this copy succeeds, "rep movs" is executed
* again.
*/
- if ((addr & PAGE_MASK) != ((addr + sign * (size - 1)) & PAGE_MASK)) {
+ if ((addr & PAGE_MASK) != ((addr + size - 1) & PAGE_MASK)) {
+ /* one movs crosses page border */
unsigned long value = 0;
mmio_opp->flags |= OVERLAP;
@@ -876,15 +884,14 @@
hvm_copy(&value, addr, size, HVM_COPY_IN);
send_mmio_req(IOREQ_TYPE_COPY, gpa, 1, size, value, dir, 0);
} else {
- if ((addr & PAGE_MASK) != ((addr + sign * (count * size - 1)) &
PAGE_MASK)) {
+ if ((high_addr & PAGE_MASK) != (low_addr & PAGE_MASK)) {
+ /* $count movs will cross page border */
regs->eip -= inst_len; /* do not advance %eip */
-
- if (sign > 0)
- count = (PAGE_SIZE - (addr & ~PAGE_MASK)) / size;
- else
- count = (addr & ~PAGE_MASK) / size;
+ if (sign > 0)
+ count = (PAGE_SIZE - (addr & ~PAGE_MASK)) / size;
+ else
+ count = ((high_addr + size - 1) & ~PAGE_MASK) / size;
}
-
send_mmio_req(IOREQ_TYPE_COPY, gpa, count, size, addr, dir, 1);
}
break;
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