fpu: Fix fp_xsave_size meaning confusion

It was meant to be the size of the whole ifps, but then it was mistaken as
the xsave size. Switch to that meaning, and add to it the offset as
appropriate.

2 files changed, 14 insertions, 13 deletions

diff --git a/i386/i386/fpu.c b/i386/i386/fpu.c
index 18440ad0..3937ffb0 100644
--- a/i386/i386/fpu.c
+++ b/i386/i386/fpu.c
@@ -77,7 +77,7 @@ _Static_assert(sizeof(struct i386_xfp_save) == 512 + 8*8,
 int			fp_kind = FP_387;	/* 80387 present */
 enum fp_save_kind	fp_save_kind = FP_FNSAVE;	/* Which instruction we use to save/restore FPU state */
 uint64_t		fp_xsave_support;	/* Bitmap of supported XSAVE save areas */
-unsigned		fp_xsave_size = sizeof(struct i386_fpsave_state);
+unsigned		fp_xsave_size = sizeof(struct i386_xfp_save);	/* size saved by XSAVE */
 struct i386_fpsave_state *fp_default_state;
 struct kmem_cache	ifps_cache;	/* cache for FPU save area */
 static unsigned long	mxcsr_feature_mask = 0xffffffff;	/* Always AND user-provided mxcsr with this security mask */
@@ -182,12 +182,12 @@ init_fpu(void)
 
 		    if (xsave_cpu_features & CPU_FEATURE_XSAVES) {
 			// all states enabled by XCR0|IA32_XSS
-			fp_xsave_size = offsetof(struct i386_fpsave_state, xfp_save_state) + ebx;
-			if (fp_xsave_size < sizeof(struct i386_fpsave_state))
+			fp_xsave_size = ebx;
+			if (fp_xsave_size < sizeof(struct i386_xfp_save))
 				panic("CPU-provided xstate size %d "
 				      "is smaller than our minimum %d!\n",
 				      fp_xsave_size,
-				      (int) sizeof(struct i386_fpsave_state));
+				      (int) sizeof(struct i386_xfp_save));
 
 			fp_save_kind = FP_XSAVES;
 		    } else {
@@ -195,12 +195,12 @@ init_fpu(void)
 			ecx = 0x0;
 			cpuid(eax, ebx, ecx, edx);
 			// all states enabled by XCR0
-			fp_xsave_size = offsetof(struct i386_fpsave_state, xfp_save_state) + ebx;
-			if(fp_xsave_size < sizeof(struct i386_fpsave_state))
+			fp_xsave_size = ebx;
+			if(fp_xsave_size < sizeof(struct i386_xfp_save))
 				panic("CPU-provided xstate size %d "
 				      "is smaller than our minimum %d!\n",
 				      fp_xsave_size,
-				      (int) sizeof(struct i386_fpsave_state));
+				      (int) sizeof(struct i386_xfp_save));
 
 			if (xsave_cpu_features & CPU_FEATURE_XSAVEOPT)
 			    fp_save_kind = FP_XSAVEOPT;
@@ -268,12 +268,12 @@ void
 fpu_module_init(void)
 {
 	kmem_cache_init(&ifps_cache, "i386_fpsave_state",
-			fp_xsave_size,
+			offsetof(struct i386_fpsave_state, xfp_save_state) + fp_xsave_size,
 			alignof(struct i386_fpsave_state),
 			NULL, 0);
 
 	fp_default_state = (struct i386_fpsave_state *) kmem_cache_alloc(&ifps_cache);
-	memset(fp_default_state, 0, fp_xsave_size);
+	memset(fp_default_state, 0, offsetof(struct i386_fpsave_state, xfp_save_state) + fp_xsave_size);
 
 	/* Get default state from CPU.  */
 	clear_ts();
@@ -445,7 +445,7 @@ ASSERT_IPL(SPL0);
 	    /*
 	     * Ensure that reserved parts of the environment are 0.
 	     */
-	    memset(ifps, 0, fp_xsave_size);
+	    memset(ifps, 0, offsetof(struct i386_fpsave_state, xfp_save_state) + fp_xsave_size);
 	    ifps->fp_valid = TRUE;
 
 	    if (flavor == i386_FLOAT_STATE) {
@@ -544,9 +544,9 @@ ASSERT_IPL(SPL0);
 	     */
 	    simple_unlock(&pcb->lock);
             if (flavor == i386_FLOAT_STATE)
-                memset(state, 0, sizeof(struct i386_float_state));
+                memset(fstate, 0, sizeof(struct i386_float_state));
             else if (flavor == i386_XFLOAT_STATE)
-                memset(state, 0, fp_xsave_size);
+                memset(xfstate, 0, sizeof(struct i386_xfloat_state) + fp_xsave_size);
 	    return KERN_SUCCESS;
 	}
 
@@ -936,7 +936,7 @@ ASSERT_IPL(SPL0);
 	ifps = pcb->ims.ifps;
 	if (ifps == 0) {
 	    ifps = (struct i386_fpsave_state *) kmem_cache_alloc(&ifps_cache);
-	    memcpy(ifps, fp_default_state, fp_xsave_size);
+	    memcpy(ifps, fp_default_state, offsetof(struct i386_fpsave_state, xfp_save_state) + fp_xsave_size);
 	    pcb->ims.ifps = ifps;
 	    fpinit(thread);
 #if 1
diff --git a/i386/i386/fpu.h b/i386/i386/fpu.h
index df347a26..7c9fd31d 100644
--- a/i386/i386/fpu.h
+++ b/i386/i386/fpu.h
@@ -234,6 +234,7 @@ extern void fp_save(thread_t thread);
 extern void fp_load(thread_t thread);
 extern void fp_free(struct i386_fpsave_state *fps);
 extern void fpu_module_init(void);
+extern kern_return_t i386_get_xstate_size(host_t host, vm_size_t *size);
 extern kern_return_t fpu_set_state(thread_t thread, void *state, int flavor);
 extern kern_return_t fpu_get_state(thread_t thread, void *state, int flavor);
 extern void fpnoextflt(void);