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| author | Avi Kivity <avi@qumranet.com> | 2007-07-22 18:48:54 +0300 |
|---|---|---|
| committer | Avi Kivity <avi@qumranet.com> | 2007-07-25 14:29:17 +0300 |
| commit | b0fcd903e6f3f47189baddf3fe085bdf78c9644c (patch) | |
| tree | c3c0e098b25d158973a7262865e74ae790a66772 /drivers/kvm/kvm_main.c | |
| parent | 0de085bb474f64e4fdb2f1ff3268590792648c7b (diff) | |
| download | lwn-b0fcd903e6f3f47189baddf3fe085bdf78c9644c.tar.gz lwn-b0fcd903e6f3f47189baddf3fe085bdf78c9644c.zip | |
KVM: Correctly handle writes crossing a page boundary
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>
Diffstat (limited to 'drivers/kvm/kvm_main.c')
| -rw-r--r-- | drivers/kvm/kvm_main.c | 28 |
1 files changed, 24 insertions, 4 deletions
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c index bcbe6835beb4..a0a3fddba815 100644 --- a/drivers/kvm/kvm_main.c +++ b/drivers/kvm/kvm_main.c @@ -1078,10 +1078,10 @@ static int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa, return 1; } -static int emulator_write_emulated(unsigned long addr, - const void *val, - unsigned int bytes, - struct x86_emulate_ctxt *ctxt) +static int emulator_write_emulated_onepage(unsigned long addr, + const void *val, + unsigned int bytes, + struct x86_emulate_ctxt *ctxt) { struct kvm_vcpu *vcpu = ctxt->vcpu; struct kvm_io_device *mmio_dev; @@ -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, |