[RFC,03/22] x86/fpu/xstate: Modify address finder prototypes to access all the possible areas

Commit Message

Chang S. Bae Oct. 1, 2020, 8:38 p.m. UTC

The xstate infrastructure is not flexible to support dynamic areas in
task->fpu. Change the prototype of some address finding functions to access
task->fpu directly. Make changes for both outer and inner helpers:
get_xsave_addr() and __raw_xsave_addr().

No functional change.

Signed-off-by: Chang S. Bae <[e-mail]>
Reviewed-by: Len Brown <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
---
 arch/x86/include/asm/fpu/internal.h |  2 +-
 arch/x86/include/asm/fpu/xstate.h   |  2 +-
 arch/x86/include/asm/pgtable.h      |  2 +-
 arch/x86/kernel/cpu/common.c        |  2 +-
 arch/x86/kernel/fpu/xstate.c        | 43 ++++++++++++++++++++---------
 arch/x86/kvm/x86.c                  | 26 +++++++++++------
 arch/x86/mm/pkeys.c                 |  2 +-
 7 files changed, 52 insertions(+), 27 deletions(-)

Patch

diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index c404fedf1a75..baca80e877a6 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -578,7 +578,7 @@  static inline void switch_fpu_finish(struct fpu *new_fpu)
 	 * return to userland e.g. for a copy_to_user() operation.
 	 */
 	if (current->mm) {
-		pk = get_xsave_addr(&new_fpu->state.xsave, XFEATURE_PKRU);
+		pk = get_xsave_addr(new_fpu, XFEATURE_PKRU);
 		if (pk)
 			pkru_val = pk->pkru;
 	}
diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index a315b055212f..3fbf45727ad6 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -100,7 +100,7 @@  extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
 extern void __init update_regset_xstate_info(unsigned int size,
 					     u64 xstate_mask);
 
-void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr);
+void *get_xsave_addr(struct fpu *fpu, int xfeature_nr);
 const void *get_xsave_field_ptr(int xfeature_nr);
 int using_compacted_format(void);
 int xfeature_size(int xfeature_nr);
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index b836138ce852..e24a8fb8f479 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -142,7 +142,7 @@  static inline void write_pkru(u32 pkru)
 	if (!boot_cpu_has(X86_FEATURE_OSPKE))
 		return;
 
-	pk = get_xsave_addr(&current->thread.fpu.state.xsave, XFEATURE_PKRU);
+	pk = get_xsave_addr(&current->thread.fpu, XFEATURE_PKRU);
 
 	/*
 	 * The PKRU value in xstate needs to be in sync with the value that is
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index d0363e15ec2e..183ee7f77065 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -478,7 +478,7 @@  static __always_inline void setup_pku(struct cpuinfo_x86 *c)
 		return;
 
 	cr4_set_bits(X86_CR4_PKE);
-	pk = get_xsave_addr(&init_fpstate.xsave, XFEATURE_PKRU);
+	pk = get_xsave_addr(NULL, XFEATURE_PKRU);
 	if (pk)
 		pk->pkru = init_pkru_value;
 	/*
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index e3a9bddc39d9..bab22766b79b 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -891,15 +891,23 @@  void fpu__resume_cpu(void)
  * buffer the state is.  Callers should ensure that the buffer
  * is valid.
  */
-static void *__raw_xsave_addr(struct xregs_state *xsave, int xfeature_nr)
+static void *__raw_xsave_addr(struct fpu *fpu, int xfeature_nr)
 {
+	void *xsave;
+
 	if (!xfeature_enabled(xfeature_nr)) {
 		WARN_ON_FPU(1);
 		return NULL;
 	}
 
-	return (void *)xsave + xstate_comp_offsets[xfeature_nr];
+	if (fpu)
+		xsave = &fpu->state.xsave;
+	else
+		xsave = &init_fpstate.xsave;
+
+	return xsave + xstate_comp_offsets[xfeature_nr];
 }
+
 /*
  * Given the xsave area and a state inside, this function returns the
  * address of the state.
@@ -911,15 +919,18 @@  static void *__raw_xsave_addr(struct xregs_state *xsave, int xfeature_nr)
  * this will return NULL.
  *
  * Inputs:
- *	xstate: the thread's storage area for all FPU data
+ *	fpu: the thread's FPU data to access all the FPU state storages.
+	     (If a null pointer is given, assume the init_fpstate)
  *	xfeature_nr: state which is defined in xsave.h (e.g. XFEATURE_FP,
  *	XFEATURE_SSE, etc...)
  * Output:
  *	address of the state in the xsave area, or NULL if the
  *	field is not present in the xsave buffer.
  */
-void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr)
+void *get_xsave_addr(struct fpu *fpu, int xfeature_nr)
 {
+	struct xregs_state *xsave;
+
 	/*
 	 * Do we even *have* xsave state?
 	 */
@@ -932,6 +943,12 @@  void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr)
 	 */
 	WARN_ONCE(!(xfeatures_mask_all & BIT_ULL(xfeature_nr)),
 		  "get of unsupported state");
+
+	if (fpu)
+		xsave = &fpu->state.xsave;
+	else
+		xsave = &init_fpstate.xsave;
+
 	/*
 	 * This assumes the last 'xsave*' instruction to
 	 * have requested that 'xfeature_nr' be saved.
@@ -946,7 +963,7 @@  void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr)
 	if (!(xsave->header.xfeatures & BIT_ULL(xfeature_nr)))
 		return NULL;
 
-	return __raw_xsave_addr(xsave, xfeature_nr);
+	return __raw_xsave_addr(fpu, xfeature_nr);
 }
 EXPORT_SYMBOL_GPL(get_xsave_addr);
 
@@ -977,7 +994,7 @@  const void *get_xsave_field_ptr(int xfeature_nr)
 	 */
 	fpu__save(fpu);
 
-	return get_xsave_addr(&fpu->state.xsave, xfeature_nr);
+	return get_xsave_addr(fpu, xfeature_nr);
 }
 
 #ifdef CONFIG_ARCH_HAS_PKEYS
@@ -1112,7 +1129,7 @@  void copy_xstate_to_kernel(struct membuf to, struct fpu *fpu)
 		 * Copy only in-use xstates:
 		 */
 		if ((header.xfeatures >> i) & 1) {
-			void *src = __raw_xsave_addr(xsave, i);
+			void *src = __raw_xsave_addr(fpu, i);
 
 			copy_part(&to, &last, xstate_offsets[i],
 				  xstate_sizes[i], src);
@@ -1141,13 +1158,11 @@  int copy_kernel_to_xstate(struct fpu *fpu, const void *kbuf)
 	if (validate_user_xstate_header(&hdr))
 		return -EINVAL;
 
-	xsave = &fpu->state.xsave;
-
 	for (i = 0; i < XFEATURE_MAX; i++) {
 		u64 mask = ((u64)1 << i);
 
 		if (hdr.xfeatures & mask) {
-			void *dst = __raw_xsave_addr(xsave, i);
+			void *dst = __raw_xsave_addr(fpu, i);
 
 			offset = xstate_offsets[i];
 			size = xstate_sizes[i];
@@ -1156,6 +1171,8 @@  int copy_kernel_to_xstate(struct fpu *fpu, const void *kbuf)
 		}
 	}
 
+	xsave = &fpu->state.xsave;
+
 	if (xfeatures_mxcsr_quirk(hdr.xfeatures)) {
 		offset = offsetof(struct fxregs_state, mxcsr);
 		size = MXCSR_AND_FLAGS_SIZE;
@@ -1198,13 +1215,11 @@  int copy_user_to_xstate(struct fpu *fpu, const void __user *ubuf)
 	if (validate_user_xstate_header(&hdr))
 		return -EINVAL;
 
-	xsave = &fpu->state.xsave;
-
 	for (i = 0; i < XFEATURE_MAX; i++) {
 		u64 mask = ((u64)1 << i);
 
 		if (hdr.xfeatures & mask) {
-			void *dst = __raw_xsave_addr(xsave, i);
+			void *dst = __raw_xsave_addr(fpu, i);
 
 			offset = xstate_offsets[i];
 			size = xstate_sizes[i];
@@ -1214,6 +1229,8 @@  int copy_user_to_xstate(struct fpu *fpu, const void __user *ubuf)
 		}
 	}
 
+	xsave = &fpu->state.xsave;
+
 	if (xfeatures_mxcsr_quirk(hdr.xfeatures)) {
 		offset = offsetof(struct fxregs_state, mxcsr);
 		size = MXCSR_AND_FLAGS_SIZE;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9da8cb4b8589..c4b8d3705625 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4182,10 +4182,15 @@  static int kvm_vcpu_ioctl_x86_set_debugregs(struct kvm_vcpu *vcpu,
 
 static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu)
 {
-	struct xregs_state *xsave = &vcpu->arch.guest_fpu->state.xsave;
-	u64 xstate_bv = xsave->header.xfeatures;
+	struct xregs_state *xsave;
+	struct fpu *guest_fpu;
+	u64 xstate_bv;
 	u64 valid;
 
+	guest_fpu = vcpu->arch.guest_fpu;
+	xsave = &guest_fpu->state.xsave;
+	xstate_bv = xsave->header.xfeatures;
+
 	/*
 	 * Copy legacy XSAVE area, to avoid complications with CPUID
 	 * leaves 0 and 1 in the loop below.
@@ -4204,7 +4209,7 @@  static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu)
 	while (valid) {
 		u64 xfeature_mask = valid & -valid;
 		int xfeature_nr = fls64(xfeature_mask) - 1;
-		void *src = get_xsave_addr(xsave, xfeature_nr);
+		void *src = get_xsave_addr(guest_fpu, xfeature_nr);
 
 		if (src) {
 			u32 size, offset, ecx, edx;
@@ -4224,10 +4229,14 @@  static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu)
 
 static void load_xsave(struct kvm_vcpu *vcpu, u8 *src)
 {
-	struct xregs_state *xsave = &vcpu->arch.guest_fpu->state.xsave;
 	u64 xstate_bv = *(u64 *)(src + XSAVE_HDR_OFFSET);
+	struct xregs_state *xsave;
+	struct fpu *guest_fpu;
 	u64 valid;
 
+	guest_fpu = vcpu->arch.guest_fpu;
+	xsave = &guest_fpu->state.xsave;
+
 	/*
 	 * Copy legacy XSAVE area, to avoid complications with CPUID
 	 * leaves 0 and 1 in the loop below.
@@ -4247,7 +4256,7 @@  static void load_xsave(struct kvm_vcpu *vcpu, u8 *src)
 	while (valid) {
 		u64 xfeature_mask = valid & -valid;
 		int xfeature_nr = fls64(xfeature_mask) - 1;
-		void *dest = get_xsave_addr(xsave, xfeature_nr);
+		void *dest = get_xsave_addr(guest_fpu, xfeature_nr);
 
 		if (dest) {
 			u32 size, offset, ecx, edx;
@@ -9662,6 +9671,7 @@  void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 	vcpu->arch.apf.halted = false;
 
 	if (kvm_mpx_supported()) {
+		struct fpu *guest_fpu = vcpu->arch.guest_fpu;
 		void *mpx_state_buffer;
 
 		/*
@@ -9670,12 +9680,10 @@  void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 		 */
 		if (init_event)
 			kvm_put_guest_fpu(vcpu);
-		mpx_state_buffer = get_xsave_addr(&vcpu->arch.guest_fpu->state.xsave,
-					XFEATURE_BNDREGS);
+		mpx_state_buffer = get_xsave_addr(guest_fpu, XFEATURE_BNDREGS);
 		if (mpx_state_buffer)
 			memset(mpx_state_buffer, 0, sizeof(struct mpx_bndreg_state));
-		mpx_state_buffer = get_xsave_addr(&vcpu->arch.guest_fpu->state.xsave,
-					XFEATURE_BNDCSR);
+		mpx_state_buffer = get_xsave_addr(guest_fpu, XFEATURE_BNDCSR);
 		if (mpx_state_buffer)
 			memset(mpx_state_buffer, 0, sizeof(struct mpx_bndcsr));
 		if (init_event)
diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
index 8873ed1438a9..772e8bc3d49d 100644
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -177,7 +177,7 @@  static ssize_t init_pkru_write_file(struct file *file,
 		return -EINVAL;
 
 	WRITE_ONCE(init_pkru_value, new_init_pkru);
-	pk = get_xsave_addr(&init_fpstate.xsave, XFEATURE_PKRU);
+	pk = get_xsave_addr(NULL, XFEATURE_PKRU);
 	if (!pk)
 		return -EINVAL;
 	pk->pkru = new_init_pkru;