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KVM: Correctly handle writes crossing a page boundary

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Writes that are contiguous in virtual memory may not be contiguous in
physical memory; so split writes that straddle a page boundary.

Thanks to Aurelien for reporting the bug, patient testing, and a fix
to this very patch.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Avi Kivity 2007-07-22 18:48:54 +03:00
parent 0de085bb47
commit b0fcd903e6
1 changed files with 24 additions and 4 deletions
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22
drivers/kvm/kvm_main.c
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@ -1078,7 +1078,7 @@ static int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
return 1;
}
static int emulator_write_emulated(unsigned long addr,
static int emulator_write_emulated_onepage(unsigned long addr,
const void *val,
unsigned int bytes,
struct x86_emulate_ctxt *ctxt)
@ -1113,6 +1113,26 @@ static int emulator_write_emulated(unsigned long addr,
return X86EMUL_CONTINUE;
}
static int emulator_write_emulated(unsigned long addr,
const void *val,
unsigned int bytes,
struct x86_emulate_ctxt *ctxt)
{
/* Crossing a page boundary? */
if (((addr + bytes - 1) ^ addr) & PAGE_MASK) {
int rc, now;
now = -addr & ~PAGE_MASK;
rc = emulator_write_emulated_onepage(addr, val, now, ctxt);
if (rc != X86EMUL_CONTINUE)
return rc;
addr += now;
val += now;
bytes -= now;
}
return emulator_write_emulated_onepage(addr, val, bytes, ctxt);
}
static int emulator_cmpxchg_emulated(unsigned long addr,
const void *old,
const void *new,