Have all the functions finding xstate address take a struct fpu * pointer
in preparation for dynamic state buffer support.

init_fpstate is a special case, which is indicated by a null pointer
parameter to get_xsave_addr() and __raw_xsave_addr().

No functional change.

Signed-off-by: Chang S. Bae <chang.seok....@intel.com>
Reviewed-by: Len Brown <len.br...@intel.com>
Cc: x...@kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: k...@vger.kernel.org
---
Changes from v3:
* Updated the changelog. (Borislav Petkov)
* Updated the function comment to use kernel-doc style. (Borislav Petkov)

Changes from v2:
* Updated the changelog with task->fpu removed. (Borislav Petkov)

Changes from v1:
* Rebased on the upstream kernel (5.10)
---
 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        | 38 +++++++++++++++++++++--------
 arch/x86/kvm/x86.c                  | 10 +++-----
 arch/x86/mm/pkeys.c                 |  2 +-
 7 files changed, 37 insertions(+), 21 deletions(-)

diff --git a/arch/x86/include/asm/fpu/internal.h 
b/arch/x86/include/asm/fpu/internal.h
index d81d8c407dc0..0153c4d4ca77 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -579,7 +579,7 @@ 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 e0f1b22f53ce..24bf8d3f559a 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 a02c67291cfc..83268b41444f 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -141,7 +141,7 @@ 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 35ad8480c464..860b19db208b 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 6156dad0feb6..5401a71dd15e 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -894,15 +894,24 @@ void fpu__resume_cpu(void)
  * Given an xstate feature nr, calculate where in the xsave
  * buffer the state is.  Callers should ensure that the buffer
  * is valid.
+ *
+ * @fpu: If NULL, use init_fpstate
  */
-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
@@ -915,15 +924,18 @@ 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 reference xstate buffer(s).
+ *          (A null pointer parameter indicates 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?
         */
@@ -936,6 +948,12 @@ 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.
@@ -950,7 +968,7 @@ 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);
 
@@ -981,7 +999,7 @@ 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
@@ -1116,7 +1134,7 @@ 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);
@@ -1151,7 +1169,7 @@ int copy_kernel_to_xstate(struct fpu *fpu, const void 
*kbuf)
                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];
@@ -1208,7 +1226,7 @@ int copy_user_to_xstate(struct fpu *fpu, const void 
__user *ubuf)
                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];
@@ -1450,7 +1468,7 @@ void update_pasid(void)
                 */
                xsave = &fpu->state.xsave;
                xsave->header.xfeatures |= XFEATURE_MASK_PASID;
-               ppasid_state = get_xsave_addr(xsave, XFEATURE_PASID);
+               ppasid_state = get_xsave_addr(fpu, XFEATURE_PASID);
                /*
                 * Since XFEATURE_MASK_PASID is set in xfeatures, ppasid_state
                 * won't be NULL and no need to check its value.
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b933d005d45e..cc3b604ddcd2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4461,7 +4461,7 @@ 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(vcpu->arch.guest_fpu, xfeature_nr);
 
                if (src) {
                        u32 size, offset, ecx, edx;
@@ -4504,7 +4504,7 @@ 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(vcpu->arch.guest_fpu, xfeature_nr);
 
                if (dest) {
                        u32 size, offset, ecx, edx;
@@ -10140,12 +10140,10 @@ 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(vcpu->arch.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(vcpu->arch.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;
-- 
2.17.1

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