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>
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@ -1078,10 +1078,10 @@ static int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
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return 1;
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return 1;
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}
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}
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static int emulator_write_emulated(unsigned long addr,
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static int emulator_write_emulated_onepage(unsigned long addr,
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const void *val,
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const void *val,
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unsigned int bytes,
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unsigned int bytes,
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struct x86_emulate_ctxt *ctxt)
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struct x86_emulate_ctxt *ctxt)
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{
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{
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struct kvm_vcpu *vcpu = ctxt->vcpu;
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struct kvm_vcpu *vcpu = ctxt->vcpu;
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struct kvm_io_device *mmio_dev;
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struct kvm_io_device *mmio_dev;
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@ -1113,6 +1113,26 @@ static int emulator_write_emulated(unsigned long addr,
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return X86EMUL_CONTINUE;
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return X86EMUL_CONTINUE;
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}
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}
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static int emulator_write_emulated(unsigned long addr,
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const void *val,
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unsigned int bytes,
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struct x86_emulate_ctxt *ctxt)
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{
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/* Crossing a page boundary? */
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if (((addr + bytes - 1) ^ addr) & PAGE_MASK) {
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int rc, now;
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now = -addr & ~PAGE_MASK;
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rc = emulator_write_emulated_onepage(addr, val, now, ctxt);
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if (rc != X86EMUL_CONTINUE)
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return rc;
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addr += now;
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val += now;
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bytes -= now;
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}
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return emulator_write_emulated_onepage(addr, val, bytes, ctxt);
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}
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static int emulator_cmpxchg_emulated(unsigned long addr,
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static int emulator_cmpxchg_emulated(unsigned long addr,
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const void *old,
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const void *old,
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const void *new,
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const void *new,
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