5 files changed, 64 insertions, 33 deletions
diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h
index b774c52e5411..dcd9503b1098 100644
--- a/arch/x86/include/asm/fpu/api.h
+++ b/arch/x86/include/asm/fpu/api.h
@@ -62,4 +62,16 @@ extern void switch_fpu_return(void);
  */
 extern int cpu_has_xfeatures(u64 xfeatures_mask, const char **feature_name);
 
+/*
+ * Tasks that are not using SVA have mm->pasid set to zero to note that they
+ * will not have the valid bit set in MSR_IA32_PASID while they are running.
+ */
+#define PASID_DISABLED	0
+
+#ifdef CONFIG_IOMMU_SUPPORT
+/* Update current's PASID MSR/state by mm's PASID. */
+void update_pasid(void);
+#else
+static inline void update_pasid(void) { }
+#endif
 #endif /* _ASM_X86_FPU_API_H */
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 0a460f2a3f90..8d33ad80704f 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -19,6 +19,7 @@
 #include <asm/user.h>
 #include <asm/fpu/api.h>
 #include <asm/fpu/xstate.h>
+#include <asm/fpu/xcr.h>
 #include <asm/cpufeature.h>
 #include <asm/trace/fpu.h>
 
@@ -583,38 +584,13 @@ static inline void switch_fpu_finish(struct fpu *new_fpu)
 			pkru_val = pk->pkru;
 	}
 	__write_pkru(pkru_val);
-}
-
-/*
- * MXCSR and XCR definitions:
- */
-
-static inline void ldmxcsr(u32 mxcsr)
-{
-	asm volatile("ldmxcsr %0" :: "m" (mxcsr));
-}
-
-extern unsigned int mxcsr_feature_mask;
-
-#define XCR_XFEATURE_ENABLED_MASK	0x00000000
 
-static inline u64 xgetbv(u32 index)
-{
-	u32 eax, edx;
-
-	asm volatile(".byte 0x0f,0x01,0xd0" /* xgetbv */
-		     : "=a" (eax), "=d" (edx)
-		     : "c" (index));
-	return eax + ((u64)edx << 32);
-}
-
-static inline void xsetbv(u32 index, u64 value)
-{
-	u32 eax = value;
-	u32 edx = value >> 32;
-
-	asm volatile(".byte 0x0f,0x01,0xd1" /* xsetbv */
-		     : : "a" (eax), "d" (edx), "c" (index));
+	/*
+	 * Expensive PASID MSR write will be avoided in update_pasid() because
+	 * TIF_NEED_FPU_LOAD was set. And the PASID state won't be updated
+	 * unless it's different from mm->pasid to reduce overhead.
+	 */
+	update_pasid();
 }
 
 #endif /* _ASM_X86_FPU_INTERNAL_H */
diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h
index c87364ea6446..f5a38a5f3ae1 100644
--- a/arch/x86/include/asm/fpu/types.h
+++ b/arch/x86/include/asm/fpu/types.h
@@ -114,7 +114,7 @@ enum xfeature {
 	XFEATURE_Hi16_ZMM,
 	XFEATURE_PT_UNIMPLEMENTED_SO_FAR,
 	XFEATURE_PKRU,
-	XFEATURE_RSRVD_COMP_10,
+	XFEATURE_PASID,
 	XFEATURE_RSRVD_COMP_11,
 	XFEATURE_RSRVD_COMP_12,
 	XFEATURE_RSRVD_COMP_13,
@@ -134,6 +134,7 @@ enum xfeature {
 #define XFEATURE_MASK_Hi16_ZMM		(1 << XFEATURE_Hi16_ZMM)
 #define XFEATURE_MASK_PT		(1 << XFEATURE_PT_UNIMPLEMENTED_SO_FAR)
 #define XFEATURE_MASK_PKRU		(1 << XFEATURE_PKRU)
+#define XFEATURE_MASK_PASID		(1 << XFEATURE_PASID)
 #define XFEATURE_MASK_LBR		(1 << XFEATURE_LBR)
 
 #define XFEATURE_MASK_FPSSE		(XFEATURE_MASK_FP | XFEATURE_MASK_SSE)
@@ -256,6 +257,14 @@ struct arch_lbr_state {
 	struct lbr_entry		entries[];
 } __packed;
 
+/*
+ * State component 10 is supervisor state used for context-switching the
+ * PASID state.
+ */
+struct ia32_pasid_state {
+	u64 pasid;
+} __packed;
+
 struct xstate_header {
 	u64				xfeatures;
 	u64				xcomp_bv;
diff --git a/arch/x86/include/asm/fpu/xcr.h b/arch/x86/include/asm/fpu/xcr.h
new file mode 100644
index 000000000000..1c7ab8d95da5
--- /dev/null
+++ b/arch/x86/include/asm/fpu/xcr.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_FPU_XCR_H
+#define _ASM_X86_FPU_XCR_H
+
+/*
+ * MXCSR and XCR definitions:
+ */
+
+static inline void ldmxcsr(u32 mxcsr)
+{
+	asm volatile("ldmxcsr %0" :: "m" (mxcsr));
+}
+
+extern unsigned int mxcsr_feature_mask;
+
+#define XCR_XFEATURE_ENABLED_MASK	0x00000000
+
+static inline u64 xgetbv(u32 index)
+{
+	u32 eax, edx;
+
+	asm volatile("xgetbv" : "=a" (eax), "=d" (edx) : "c" (index));
+	return eax + ((u64)edx << 32);
+}
+
+static inline void xsetbv(u32 index, u64 value)
+{
+	u32 eax = value;
+	u32 edx = value >> 32;
+
+	asm volatile("xsetbv" :: "a" (eax), "d" (edx), "c" (index));
+}
+
+#endif /* _ASM_X86_FPU_XCR_H */
diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 14ab815132d4..47a92232d595 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -35,7 +35,7 @@
 				      XFEATURE_MASK_BNDCSR)
 
 /* All currently supported supervisor features */
-#define XFEATURE_MASK_SUPERVISOR_SUPPORTED (0)
+#define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID)
 
 /*
  * A supervisor state component may not always contain valuable information,