[xen staging] x86/fpu: Create a typedef for the x87/SSE area inside "struct xsave_struct"

[patchbot@xxxxxxx]

commit 4fe446a42910cb6bf53ca3a8b7c2c6a64e2f192c
Author:     Alejandro Vallejo <alejandro.vallejo@xxxxxxxxx>
AuthorDate: Thu Aug 1 09:39:11 2024 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Aug 1 09:39:11 2024 +0200

    x86/fpu: Create a typedef for the x87/SSE area inside "struct xsave_struct"
    
    Making the union non-anonymous would cause a lot of headaches, because a 
lot of
    code relies on it being so, but it's possible to make a typedef of the 
anonymous
    union so all callsites currently relying on typeof() can stop doing so 
directly.
    
    This commit creates a `fpusse_t` typedef to the anonymous union at the head 
of
    the XSAVE area and uses it instead of typeof().
    
    No functional change.
    
    Signed-off-by: Alejandro Vallejo <alejandro.vallejo@xxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/hvm/emulate.c        | 5 ++---
 xen/arch/x86/i387.c               | 8 ++++----
 xen/arch/x86/include/asm/xstate.h | 2 ++
 xen/arch/x86/xstate.c             | 2 +-
 4 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index b6ca5cb9d1..feb4792cc5 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -2363,8 +2363,7 @@ static int cf_check hvmemul_get_fpu(
         alternative_vcall(hvm_funcs.fpu_dirty_intercept);
     else if ( type == X86EMUL_FPU_fpu )
     {
-        const typeof(curr->arch.xsave_area->fpu_sse) *fpu_ctxt =
-            curr->arch.fpu_ctxt;
+        const fpusse_t *fpu_ctxt = curr->arch.fpu_ctxt;
 
         /*
          * Latch current register state so that we can back out changes
@@ -2404,7 +2403,7 @@ static void cf_check hvmemul_put_fpu(
 
     if ( aux )
     {
-        typeof(curr->arch.xsave_area->fpu_sse) *fpu_ctxt = curr->arch.fpu_ctxt;
+        fpusse_t *fpu_ctxt = curr->arch.fpu_ctxt;
         bool dval = aux->dval;
         int mode = hvm_guest_x86_mode(curr);
 
diff --git a/xen/arch/x86/i387.c b/xen/arch/x86/i387.c
index 400c70114a..134e0bece5 100644
--- a/xen/arch/x86/i387.c
+++ b/xen/arch/x86/i387.c
@@ -39,7 +39,7 @@ static inline void fpu_xrstor(struct vcpu *v, uint64_t mask)
 /* Restore x87 FPU, MMX, SSE and SSE2 state */
 static inline void fpu_fxrstor(struct vcpu *v)
 {
-    const typeof(v->arch.xsave_area->fpu_sse) *fpu_ctxt = v->arch.fpu_ctxt;
+    const fpusse_t *fpu_ctxt = v->arch.fpu_ctxt;
 
     /*
      * Some CPUs don't save/restore FDP/FIP/FOP unless an exception
@@ -151,7 +151,7 @@ static inline void fpu_xsave(struct vcpu *v)
 /* Save x87 FPU, MMX, SSE and SSE2 state */
 static inline void fpu_fxsave(struct vcpu *v)
 {
-    typeof(v->arch.xsave_area->fpu_sse) *fpu_ctxt = v->arch.fpu_ctxt;
+    fpusse_t *fpu_ctxt = v->arch.fpu_ctxt;
     unsigned int fip_width = v->domain->arch.x87_fip_width;
 
     if ( fip_width != 4 )
@@ -315,7 +315,7 @@ int vcpu_init_fpu(struct vcpu *v)
                                     __alignof(v->arch.xsave_area->fpu_sse));
         if ( v->arch.fpu_ctxt )
         {
-            typeof(v->arch.xsave_area->fpu_sse) *fpu_sse = v->arch.fpu_ctxt;
+            fpusse_t *fpu_sse = v->arch.fpu_ctxt;
 
             fpu_sse->fcw = FCW_DEFAULT;
             fpu_sse->mxcsr = MXCSR_DEFAULT;
@@ -336,7 +336,7 @@ void vcpu_setup_fpu(struct vcpu *v, struct xsave_struct 
*xsave_area,
      * accesses through both pointers alias one another, and the shorter form
      * is used here.
      */
-    typeof(xsave_area->fpu_sse) *fpu_sse = v->arch.fpu_ctxt;
+    fpusse_t *fpu_sse = v->arch.fpu_ctxt;
 
     ASSERT(!xsave_area || xsave_area == v->arch.xsave_area);
 
diff --git a/xen/arch/x86/include/asm/xstate.h 
b/xen/arch/x86/include/asm/xstate.h
index f0eeb13b87..ebeb2a3dca 100644
--- a/xen/arch/x86/include/asm/xstate.h
+++ b/xen/arch/x86/include/asm/xstate.h
@@ -82,6 +82,8 @@ struct __attribute__((aligned (64))) xsave_struct
     char data[];                             /* Variable layout states */
 };
 
+typedef typeof(((struct xsave_struct){}).fpu_sse) fpusse_t;
+
 struct xstate_bndcsr {
     uint64_t bndcfgu;
     uint64_t bndstatus;
diff --git a/xen/arch/x86/xstate.c b/xen/arch/x86/xstate.c
index 68cdd8fcf0..5c4144d55e 100644
--- a/xen/arch/x86/xstate.c
+++ b/xen/arch/x86/xstate.c
@@ -846,7 +846,7 @@ void xstate_init(struct cpuinfo_x86 *c)
 
     if ( bsp )
     {
-        static typeof(current->arch.xsave_area->fpu_sse) __initdata ctxt;
+        static fpusse_t __initdata ctxt;
 
         asm ( "fxsave %0" : "=m" (ctxt) );
         if ( ctxt.mxcsr_mask )
--
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