x86/fpu: Use fpstate in __copy_xstate_to_uabi_buf()

With dynamically enabled features the copy function must know the features
and the size which is valid for the task. Retrieve them from fpstate.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211013145323.181495492@linutronix.de

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 052e5ef..04fef47 100644 (file)
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -187,15 +187,15 @@ EXPORT_SYMBOL_GPL(fpu_swap_kvm_fpu);
 void fpu_copy_fpstate_to_kvm_uabi(struct fpu *fpu, void *buf,
                               unsigned int size, u32 pkru)
 {
-       union fpregs_state *kstate = &fpu->fpstate->regs;
+       struct fpstate *kstate = fpu->fpstate;
        union fpregs_state *ustate = buf;
        struct membuf mb = { .p = buf, .left = size };
 
        if (cpu_feature_enabled(X86_FEATURE_XSAVE)) {
-               __copy_xstate_to_uabi_buf(mb, &kstate->xsave, pkru,
-                                         XSTATE_COPY_XSAVE);
+               __copy_xstate_to_uabi_buf(mb, kstate, pkru, XSTATE_COPY_XSAVE);
        } else {
-               memcpy(&ustate->fxsave, &kstate->fxsave, sizeof(ustate->fxsave));
+               memcpy(&ustate->fxsave, &kstate->regs.fxsave,
+                      sizeof(ustate->fxsave));
                /* Make it restorable on a XSAVE enabled host */
                ustate->xsave.header.xfeatures = XFEATURE_MASK_FPSSE;
        }

diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 4beb010..54cc0a4 100644 (file)
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -969,7 +969,7 @@ static void copy_feature(bool from_xstate, struct membuf *to, void *xstate,
 /**
  * __copy_xstate_to_uabi_buf - Copy kernel saved xstate to a UABI buffer
  * @to:                membuf descriptor
- * @xsave:     The xsave from which to copy
+ * @fpstate:   The fpstate buffer from which to copy
  * @pkru_val:  The PKRU value to store in the PKRU component
  * @copy_mode: The requested copy mode
  *
@@ -979,11 +979,12 @@ static void copy_feature(bool from_xstate, struct membuf *to, void *xstate,
  *
  * It supports partial copy but @to.pos always starts from zero.
  */
-void __copy_xstate_to_uabi_buf(struct membuf to, struct xregs_state *xsave,
+void __copy_xstate_to_uabi_buf(struct membuf to, struct fpstate *fpstate,
                               u32 pkru_val, enum xstate_copy_mode copy_mode)
 {
        const unsigned int off_mxcsr = offsetof(struct fxregs_state, mxcsr);
        struct xregs_state *xinit = &init_fpstate.regs.xsave;
+       struct xregs_state *xsave = &fpstate->regs.xsave;
        struct xstate_header header;
        unsigned int zerofrom;
        u64 mask;
@@ -1003,7 +1004,7 @@ void __copy_xstate_to_uabi_buf(struct membuf to, struct xregs_state *xsave,
                break;
 
        case XSTATE_COPY_XSAVE:
-               header.xfeatures &= xfeatures_mask_uabi();
+               header.xfeatures &= fpstate->user_xfeatures;
                break;
        }
 
@@ -1046,7 +1047,7 @@ void __copy_xstate_to_uabi_buf(struct membuf to, struct xregs_state *xsave,
         * but there is no state to copy from in the compacted
         * init_fpstate. The gap tracking will zero these states.
         */
-       mask = xfeatures_mask_uabi();
+       mask = fpstate->user_xfeatures;
 
        for_each_extended_xfeature(i, mask) {
                /*
@@ -1097,7 +1098,7 @@ out:
 void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk,
                             enum xstate_copy_mode copy_mode)
 {
-       __copy_xstate_to_uabi_buf(to, &tsk->thread.fpu.fpstate->regs.xsave,
+       __copy_xstate_to_uabi_buf(to, tsk->thread.fpu.fpstate,
                                  tsk->thread.pkru, copy_mode);
 }
 

diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h
index 3e9eaf9..b74c595 100644 (file)
--- a/arch/x86/kernel/fpu/xstate.h
+++ b/arch/x86/kernel/fpu/xstate.h
@@ -15,7 +15,7 @@ static inline void xstate_init_xcomp_bv(struct xregs_state *xsave, u64 mask)
                xsave->header.xcomp_bv = mask | XCOMP_BV_COMPACTED_FORMAT;
 }
 
-extern void __copy_xstate_to_uabi_buf(struct membuf to, struct xregs_state *xsave,
+extern void __copy_xstate_to_uabi_buf(struct membuf to, struct fpstate *fpstate,
                                      u32 pkru_val, enum xstate_copy_mode copy_mode);
 
 extern void fpu__init_cpu_xstate(void);