From: Jack Lange <jarusl@cs.northwestern.edu>
Date: Sat, 14 Feb 2009 00:18:26 +0000 (-0600)
Subject: Do we need to save and restore the guests GS/FS regs?
X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?p=palacios.git;a=commitdiff_plain;h=33f53e0ad567d9b810015efacd85e8062a0efec1

Do we need to save and restore the guests GS/FS regs?
---

diff --git a/palacios/include/palacios/vm_guest.h b/palacios/include/palacios/vm_guest.h
index 46fe9f9..1eb4de6 100644
--- a/palacios/include/palacios/vm_guest.h
+++ b/palacios/include/palacios/vm_guest.h
@@ -104,7 +104,7 @@ struct v3_segments {
   struct v3_segment gdtr;
   struct v3_segment idtr;
   struct v3_segment tr;
-} ;
+};
 
 struct shadow_page_state;
 struct v3_intr_state;
@@ -170,6 +170,12 @@ struct guest_info {
   v3_msr_t guest_syscall_mask;
   v3_msr_t guest_gs_base;
 
+
+  uint64_t fs;
+  uint64_t gs;
+
+
+
 };
 
 
diff --git a/palacios/src/palacios/svm.c b/palacios/src/palacios/svm.c
index c2c7a12..18c78e1 100644
--- a/palacios/src/palacios/svm.c
+++ b/palacios/src/palacios/svm.c
@@ -45,6 +45,7 @@
 
 extern void v3_stgi();
 extern void v3_clgi();
+//extern int v3_svm_launch(vmcb_t * vmcb, struct v3_gprs * vm_regs, uint64_t * fs, uint64_t * gs);
 extern int v3_svm_launch(vmcb_t * vmcb, struct v3_gprs * vm_regs);
 
 
@@ -299,6 +300,11 @@ static void Init_VMCB_BIOS(vmcb_t * vmcb, struct guest_info *vm_info) {
   }
 
 
+  /* Safety locations for fs/gs */
+  vm_info->fs = 0;
+  vm_info->gs = 0;
+
+
 
 }
 
@@ -361,12 +367,15 @@ static int start_svm_guest(struct guest_info *info) {
 #define MSR_CSTAR     0xc0000083
 #define MSR_SF_MASK   0xc0000084
 #define MSR_GS_BASE   0xc0000101
+#define MSR_KERNGS_BASE   0xc0000102
+
 
     struct v3_msr host_cstar;
     struct v3_msr host_star;
     struct v3_msr host_lstar;
     struct v3_msr host_syscall_mask;
     struct v3_msr host_gs_base;
+    struct v3_msr host_kerngs_base;
 
     v3_enable_ints();
     v3_clgi();
@@ -384,10 +393,13 @@ static int start_svm_guest(struct guest_info *info) {
     v3_get_msr(MSR_CSTAR, &(host_cstar.hi), &(host_cstar.lo));
     v3_get_msr(MSR_SF_MASK, &(host_syscall_mask.hi), &(host_syscall_mask.lo));
     v3_get_msr(MSR_GS_BASE, &(host_gs_base.hi), &(host_gs_base.lo));
+    v3_get_msr(MSR_KERNGS_BASE, &(host_kerngs_base.hi), &(host_kerngs_base.lo));
+
 
     rdtscll(info->time_state.cached_host_tsc);
     guest_ctrl->TSC_OFFSET = info->time_state.guest_tsc - info->time_state.cached_host_tsc;
 
+    //v3_svm_launch((vmcb_t*)V3_PAddr(info->vmm_data), &(info->vm_regs), &(info->fs), &(info->gs));
     v3_svm_launch((vmcb_t*)V3_PAddr(info->vmm_data), &(info->vm_regs));
 
     rdtscll(tmp_tsc);
@@ -397,6 +409,7 @@ static int start_svm_guest(struct guest_info *info) {
     v3_set_msr(MSR_CSTAR, host_cstar.hi, host_cstar.lo);
     v3_set_msr(MSR_SF_MASK, host_syscall_mask.hi, host_syscall_mask.lo);
     v3_set_msr(MSR_GS_BASE, host_gs_base.hi, host_gs_base.lo);
+    v3_set_msr(MSR_KERNGS_BASE, host_kerngs_base.hi, host_kerngs_base.lo);
 
     //PrintDebug("SVM Returned\n");
 
diff --git a/palacios/src/palacios/svm_lowlevel.S b/palacios/src/palacios/svm_lowlevel.S
index 151e54b..975fe98 100644
--- a/palacios/src/palacios/svm_lowlevel.S
+++ b/palacios/src/palacios/svm_lowlevel.S
@@ -158,6 +158,8 @@ v3_svm_launch:
 
 // VMCB => RDI
 // vm_regs => RSI
+// ptr to fs => RDX
+// ptr to gs => RCX
 
 v3_svm_launch:
 	pushf;
@@ -165,7 +167,20 @@ v3_svm_launch:
 	push	%gs;
 	PUSHA
 
-	pushq %rsi
+
+
+//	pushq	%rdx // fs
+//	pushq	%rcx // gs
+
+
+//	pushq	(%rdx)
+//	pop	%fs
+//	pushq	(%rcx)
+//	pop	%gs
+
+
+
+	pushq	%rsi
 
 	movq	%rdi, %rax
 	Restore_SVM_Registers(%rsi);
@@ -180,6 +195,18 @@ v3_svm_launch:
 
 	addq $8, %rsp
 
+//	popq	%rcx
+//	popq	%rdx
+
+//	push	%fs
+//	popq 	%rax
+//	movq	%rax, (%rdx)
+
+//	push	%gs
+//	popq 	%rax
+//	movq	%rax, (%rcx)
+
+
 	POPA
 	pop	%gs;
 	pop	%fs;