svn commit: r284046 - head/sys/amd64/vmm

Neel Natu neel at FreeBSD.org
Fri Jun 5 21:22:27 UTC 2015


Author: neel
Date: Fri Jun  5 21:22:26 2015
New Revision: 284046
URL: https://svnweb.freebsd.org/changeset/base/284046

Log:
  The 'verify_gla()' function is used to ensure that the effective address
  after decoding the instruction matches the one provided by hardware.
  
  Prior to r283293 'vie->num_valid' used to contain the actual length of
  the instruction whereas now it contains the maximum instruction length
  possible. This introduced a bug when calculating a RIP-relative base address.
  
  Fix this by using 'vie->num_processed' rather than 'vie->num_valid' as the
  length of the emulated instruction.
  
  Reported and tested by:	tychon
  MFC after:	1 week

Modified:
  head/sys/amd64/vmm/vmm_instruction_emul.c

Modified: head/sys/amd64/vmm/vmm_instruction_emul.c
==============================================================================
--- head/sys/amd64/vmm/vmm_instruction_emul.c	Fri Jun  5 20:38:22 2015	(r284045)
+++ head/sys/amd64/vmm/vmm_instruction_emul.c	Fri Jun  5 21:22:26 2015	(r284046)
@@ -2342,7 +2342,7 @@ verify_gla(struct vm *vm, int cpuid, uin
 		 * instruction
 		 */
 		if (vie->base_register == VM_REG_GUEST_RIP)
-			base += vie->num_valid;
+			base += vie->num_processed;
 	}
 
 	idx = 0;


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