svn commit: r272395 - head/sys/amd64/vmm/intel

[Neel Natu]

Author: neel
Date: Thu Oct  2 05:32:29 2014
New Revision: 272395
URL: https://svnweb.freebsd.org/changeset/base/272395

Log:
  Get rid of code that dealt with the hardware not being able to save/restore
  the PAT MSR on guest exit/entry. This workaround was done for a beta release
  of VMware Fusion 5 but is no longer needed in later versions.
  
  All Intel CPUs since Nehalem have supported saving and restoring MSR_PAT
  in the VM exit and entry controls.
  
  Discussed with:	grehan

Modified:
  head/sys/amd64/vmm/intel/vmx.c

Modified: head/sys/amd64/vmm/intel/vmx.c
==============================================================================
--- head/sys/amd64/vmm/intel/vmx.c	Thu Oct  2 02:00:21 2014	(r272394)
+++ head/sys/amd64/vmm/intel/vmx.c	Thu Oct  2 05:32:29 2014	(r272395)
@@ -94,23 +94,18 @@ __FBSDID("$FreeBSD$");
 #define	PROCBASED_CTLS2_ONE_SETTING	PROCBASED2_ENABLE_EPT
 #define	PROCBASED_CTLS2_ZERO_SETTING	0
 
-#define VM_EXIT_CTLS_ONE_SETTING_NO_PAT					\
+#define	VM_EXIT_CTLS_ONE_SETTING					\
 	(VM_EXIT_HOST_LMA			|			\
 	VM_EXIT_SAVE_EFER			|			\
-	VM_EXIT_LOAD_EFER)
-
-#define	VM_EXIT_CTLS_ONE_SETTING					\
-	(VM_EXIT_CTLS_ONE_SETTING_NO_PAT       	|			\
+	VM_EXIT_LOAD_EFER			|			\
 	VM_EXIT_ACKNOWLEDGE_INTERRUPT		|			\
 	VM_EXIT_SAVE_PAT			|			\
 	VM_EXIT_LOAD_PAT)
+
 #define	VM_EXIT_CTLS_ZERO_SETTING	VM_EXIT_SAVE_DEBUG_CONTROLS
 
-#define	VM_ENTRY_CTLS_ONE_SETTING_NO_PAT	VM_ENTRY_LOAD_EFER
+#define	VM_ENTRY_CTLS_ONE_SETTING	(VM_ENTRY_LOAD_EFER | VM_ENTRY_LOAD_PAT)
 
-#define	VM_ENTRY_CTLS_ONE_SETTING					\
-	(VM_ENTRY_CTLS_ONE_SETTING_NO_PAT     	|			\
-	VM_ENTRY_LOAD_PAT)
 #define	VM_ENTRY_CTLS_ZERO_SETTING					\
 	(VM_ENTRY_LOAD_DEBUG_CONTROLS		|			\
 	VM_ENTRY_INTO_SMM			|			\
@@ -152,10 +147,6 @@ SYSCTL_INT(_hw_vmm_vmx, OID_AUTO, initia
  */
 static SYSCTL_NODE(_hw_vmm_vmx, OID_AUTO, cap, CTLFLAG_RW, NULL, NULL);
 
-static int vmx_patmsr;
-SYSCTL_INT(_hw_vmm_vmx_cap, OID_AUTO, patmsr, CTLFLAG_RD, &vmx_patmsr, 0,
-    "PAT MSR saved and restored in VCMS");
-
 static int cap_halt_exit;
 SYSCTL_INT(_hw_vmm_vmx_cap, OID_AUTO, halt_exit, CTLFLAG_RD, &cap_halt_exit, 0,
     "HLT triggers a VM-exit");
@@ -615,48 +606,24 @@ vmx_init(int ipinum)
 	}
 
 	/* Check support for VM-exit controls */
-	vmx_patmsr = 1;
 	error = vmx_set_ctlreg(MSR_VMX_EXIT_CTLS, MSR_VMX_TRUE_EXIT_CTLS,
 			       VM_EXIT_CTLS_ONE_SETTING,
 			       VM_EXIT_CTLS_ZERO_SETTING,
 			       &exit_ctls);
 	if (error) {
-		/* Try again without the PAT MSR bits */
-		error = vmx_set_ctlreg(MSR_VMX_EXIT_CTLS,
-				       MSR_VMX_TRUE_EXIT_CTLS,
-				       VM_EXIT_CTLS_ONE_SETTING_NO_PAT,
-				       VM_EXIT_CTLS_ZERO_SETTING,
-				       &exit_ctls);
-		if (error) {
-			printf("vmx_init: processor does not support desired "
-			       "exit controls\n");
-			return (error);
-		} else {
-			if (bootverbose)
-				printf("vmm: PAT MSR access not supported\n");
-			vmx_patmsr = 0;
-		}
+		printf("vmx_init: processor does not support desired "
+		    "exit controls\n");
+		return (error);
 	}
 
 	/* Check support for VM-entry controls */
-	if (vmx_patmsr) {
-		error = vmx_set_ctlreg(MSR_VMX_ENTRY_CTLS,
-				       MSR_VMX_TRUE_ENTRY_CTLS,
-				       VM_ENTRY_CTLS_ONE_SETTING,
-				       VM_ENTRY_CTLS_ZERO_SETTING,
-				       &entry_ctls);
-	} else {
-		error = vmx_set_ctlreg(MSR_VMX_ENTRY_CTLS,
-				       MSR_VMX_TRUE_ENTRY_CTLS,
-				       VM_ENTRY_CTLS_ONE_SETTING_NO_PAT,
-				       VM_ENTRY_CTLS_ZERO_SETTING,
-				       &entry_ctls);
-	}
-
+	error = vmx_set_ctlreg(MSR_VMX_ENTRY_CTLS, MSR_VMX_TRUE_ENTRY_CTLS,
+	    VM_ENTRY_CTLS_ONE_SETTING, VM_ENTRY_CTLS_ZERO_SETTING,
+	    &entry_ctls);
 	if (error) {
 		printf("vmx_init: processor does not support desired "
-		       "entry controls\n");
-		       return (error);
+		    "entry controls\n");
+		return (error);
 	}
 
 	/*
@@ -889,6 +856,10 @@ vmx_vminit(struct vm *vm, pmap_t pmap)
 	 * VM exit and entry respectively. It is also restored from the
 	 * host VMCS area on a VM exit.
 	 *
+	 * MSR_PAT is saved and restored in the guest VMCS are on a VM exit
+	 * and entry respectively. It is also restored from the host VMCS
+	 * area on a VM exit.
+	 *
 	 * The TSC MSR is exposed read-only. Writes are disallowed as that
 	 * will impact the host TSC.
 	 * XXX Writes would be implemented with a wrmsr trap, and
@@ -900,19 +871,10 @@ vmx_vminit(struct vm *vm, pmap_t pmap)
 	    guest_msr_rw(vmx, MSR_SYSENTER_ESP_MSR) ||
 	    guest_msr_rw(vmx, MSR_SYSENTER_EIP_MSR) ||
 	    guest_msr_rw(vmx, MSR_EFER) ||
+	    guest_msr_rw(vmx, MSR_PAT) ||
 	    guest_msr_ro(vmx, MSR_TSC))
 		panic("vmx_vminit: error setting guest msr access");
 
-	/*
-	 * MSR_PAT is saved and restored in the guest VMCS are on a VM exit
-	 * and entry respectively. It is also restored from the host VMCS
-	 * area on a VM exit. However, if running on a system with no
-	 * MSR_PAT save/restore support, leave access disabled so accesses
-	 * will be trapped.
-	 */
-	if (vmx_patmsr && guest_msr_rw(vmx, MSR_PAT))
-		panic("vmx_vminit: error setting guest pat msr access");
-
 	vpid_alloc(vpid, VM_MAXCPU);
 
 	if (virtual_interrupt_delivery) {