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* [PATCH 1/3] KVM: x86: fix broken read emulation spans a page boundary
@ 2011-07-13  6:31 Xiao Guangrong
  2011-07-13  6:31 ` [PATCH 2/3] KVM: x86: abstract the operation for read/write emulation Xiao Guangrong
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Xiao Guangrong @ 2011-07-13  6:31 UTC (permalink / raw)
  To: Avi Kivity; +Cc: Marcelo Tosatti, LKML, KVM

If the range spans a page boundary, the mmio access can be broke, fix it as
write emulation.

And we already get the guest physical address, so use it to read guest data
directly to avoid walking guest page table again

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
 arch/x86/kvm/x86.c |   39 +++++++++++++++++++++++++++++++--------
 1 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 84a28ea..1453248 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4045,13 +4045,12 @@ static int vcpu_mmio_gva_to_gpa(struct kvm_vcpu *vcpu, unsigned long gva,
 	return 0;
 }
 
-static int emulator_read_emulated(struct x86_emulate_ctxt *ctxt,
-				  unsigned long addr,
-				  void *val,
-				  unsigned int bytes,
-				  struct x86_exception *exception)
+static int emulator_read_emulated_onepage(unsigned long addr,
+					  void *val,
+					  unsigned int bytes,
+					  struct x86_exception *exception,
+					  struct kvm_vcpu *vcpu)
 {
-	struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
 	gpa_t gpa;
 	int handled, ret;
 
@@ -4071,8 +4070,7 @@ static int emulator_read_emulated(struct x86_emulate_ctxt *ctxt,
 	if (ret)
 		goto mmio;
 
-	if (kvm_read_guest_virt(ctxt, addr, val, bytes, exception)
-	    == X86EMUL_CONTINUE)
+	if (!kvm_read_guest(vcpu->kvm, gpa, val, bytes))
 		return X86EMUL_CONTINUE;
 
 mmio:
@@ -4101,6 +4099,31 @@ mmio:
 	return X86EMUL_IO_NEEDED;
 }
 
+static int emulator_read_emulated(struct x86_emulate_ctxt *ctxt,
+				  unsigned long addr,
+				  void *val,
+				  unsigned int bytes,
+				  struct x86_exception *exception)
+{
+	struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
+
+	/* Crossing a page boundary? */
+	if (((addr + bytes - 1) ^ addr) & PAGE_MASK) {
+		int rc, now;
+
+		now = -addr & ~PAGE_MASK;
+		rc = emulator_read_emulated_onepage(addr, val, now, exception,
+							vcpu);
+		if (rc != X86EMUL_CONTINUE)
+			return rc;
+		addr += now;
+		val += now;
+		bytes -= now;
+	}
+	return emulator_read_emulated_onepage(addr, val, bytes, exception,
+						vcpu);
+}
+
 int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
 			const void *val, int bytes)
 {
-- 
1.7.5.4

^ permalink raw reply related	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2011-07-14  8:59 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2011-07-13  6:31 [PATCH 1/3] KVM: x86: fix broken read emulation spans a page boundary Xiao Guangrong
2011-07-13  6:31 ` [PATCH 2/3] KVM: x86: abstract the operation for read/write emulation Xiao Guangrong
2011-07-13  6:32 ` [PATCH 3/3] KVM: x86: cleanup the code of " Xiao Guangrong
2011-07-14  8:59 ` [PATCH 1/3] KVM: x86: fix broken read emulation spans a page boundary Avi Kivity

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