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Date:      Fri, 11 Apr 2014 20:15:53 +0000 (UTC)
From:      Neel Natu <neel@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r264353 - head/sys/amd64/vmm/intel
Message-ID:  <201404112015.s3BKFrT0026232@svn.freebsd.org>
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Author: neel
Date: Fri Apr 11 20:15:53 2014
New Revision: 264353
URL: http://svnweb.freebsd.org/changeset/base/264353

Log:
  There is no need to save and restore the host's return address in the
  'struct vmxctx'. It is preserved on the host stack across a guest entry
  and exit and just restoring the host's '%rsp' is sufficient.
  
  Pointed out by:	grehan@

Modified:
  head/sys/amd64/vmm/intel/vmx.h
  head/sys/amd64/vmm/intel/vmx_genassym.c
  head/sys/amd64/vmm/intel/vmx_support.S

Modified: head/sys/amd64/vmm/intel/vmx.h
==============================================================================
--- head/sys/amd64/vmm/intel/vmx.h	Fri Apr 11 19:27:35 2014	(r264352)
+++ head/sys/amd64/vmm/intel/vmx.h	Fri Apr 11 20:15:53 2014	(r264353)
@@ -60,7 +60,6 @@ struct vmxctx {
 	register_t	host_rbp;
 	register_t	host_rsp;
 	register_t	host_rbx;
-	register_t	host_rip;
 	/*
 	 * XXX todo debug registers and fpu state
 	 */

Modified: head/sys/amd64/vmm/intel/vmx_genassym.c
==============================================================================
--- head/sys/amd64/vmm/intel/vmx_genassym.c	Fri Apr 11 19:27:35 2014	(r264352)
+++ head/sys/amd64/vmm/intel/vmx_genassym.c	Fri Apr 11 20:15:53 2014	(r264353)
@@ -65,7 +65,6 @@ ASSYM(VMXCTX_HOST_R12, offsetof(struct v
 ASSYM(VMXCTX_HOST_RBP, offsetof(struct vmxctx, host_rbp));
 ASSYM(VMXCTX_HOST_RSP, offsetof(struct vmxctx, host_rsp));
 ASSYM(VMXCTX_HOST_RBX, offsetof(struct vmxctx, host_rbx));
-ASSYM(VMXCTX_HOST_RIP, offsetof(struct vmxctx, host_rip));
 
 ASSYM(VMXCTX_INST_FAIL_STATUS, offsetof(struct vmxctx, inst_fail_status));
 ASSYM(VMXCTX_PMAP, offsetof(struct vmxctx, pmap));

Modified: head/sys/amd64/vmm/intel/vmx_support.S
==============================================================================
--- head/sys/amd64/vmm/intel/vmx_support.S	Fri Apr 11 19:27:35 2014	(r264352)
+++ head/sys/amd64/vmm/intel/vmx_support.S	Fri Apr 11 20:15:53 2014	(r264353)
@@ -72,8 +72,7 @@
  *
  * Assumes that %rdi holds a pointer to the 'vmxctx'.
  */
-#define	VMX_HOST_SAVE(tmpreg)						\
-	movq	(%rsp), tmpreg;			/* return address */	\
+#define	VMX_HOST_SAVE							\
 	movq    %r15, VMXCTX_HOST_R15(%rdi);				\
 	movq    %r14, VMXCTX_HOST_R14(%rdi);				\
 	movq    %r13, VMXCTX_HOST_R13(%rdi);				\
@@ -81,9 +80,8 @@
 	movq    %rbp, VMXCTX_HOST_RBP(%rdi);				\
 	movq    %rsp, VMXCTX_HOST_RSP(%rdi);				\
 	movq    %rbx, VMXCTX_HOST_RBX(%rdi);				\
-	movq    tmpreg, VMXCTX_HOST_RIP(%rdi)
 
-#define	VMX_HOST_RESTORE(tmpreg)					\
+#define	VMX_HOST_RESTORE						\
 	movq	VMXCTX_HOST_R15(%rdi), %r15;				\
 	movq	VMXCTX_HOST_R14(%rdi), %r14;				\
 	movq	VMXCTX_HOST_R13(%rdi), %r13;				\
@@ -91,8 +89,6 @@
 	movq	VMXCTX_HOST_RBP(%rdi), %rbp;				\
 	movq	VMXCTX_HOST_RSP(%rdi), %rsp;				\
 	movq	VMXCTX_HOST_RBX(%rdi), %rbx;				\
-	movq	VMXCTX_HOST_RIP(%rdi), tmpreg;				\
-	movq	tmpreg, (%rsp)			/* return address */
 
 /*
  * vmx_enter_guest(struct vmxctx *vmxctx, int launched)
@@ -105,7 +101,7 @@ ENTRY(vmx_enter_guest)
 	/*
 	 * Save host state before doing anything else.
 	 */
-	VMX_HOST_SAVE(%r10)
+	VMX_HOST_SAVE
 
 	/*
 	 * Activate guest pmap on this cpu.
@@ -186,7 +182,7 @@ inst_error:
 	movl	PCPU(CPUID), %r10d
 	LK btrl	%r10d, PM_ACTIVE(%r11)
 
-	VMX_HOST_RESTORE(%r10)
+	VMX_HOST_RESTORE
 	ret
 END(vmx_enter_guest)
 
@@ -226,7 +222,7 @@ ENTRY(vmx_exit_guest)
 	movl	PCPU(CPUID), %r10d
 	LK btrl	%r10d, PM_ACTIVE(%r11)
 
-	VMX_HOST_RESTORE(%r10)
+	VMX_HOST_RESTORE
 
 	/*
 	 * This will return to the caller of 'vmx_enter_guest()' with a return

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