x86/fpu: Add a pkru argument to copy_uabi_from_kernel_to_xstate().

Both KVM (through KVM_SET_XSTATE) and ptrace (through PTRACE_SETREGSET
with NT_X86_XSTATE) ultimately call copy_uabi_from_kernel_to_xstate(),
but the canonical locations for the current PKRU value for KVM guests
and processes in a ptrace stop are different (in the kvm_vcpu_arch and
the thread_state structs respectively).

In preparation for eventually handling PKRU in
copy_uabi_to_xstate, pass in a pointer to the PKRU location.

Signed-off-by: Kyle Huey <me@kylehuey.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20221115230932.7126-3-khuey%40kylehuey.com

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 3b28c5b..5501576 100644 (file)
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -406,7 +406,7 @@ int fpu_copy_uabi_to_guest_fpstate(struct fpu_guest *gfpu, const void *buf,
        if (ustate->xsave.header.xfeatures & ~xcr0)
                return -EINVAL;
 
-       ret = copy_uabi_from_kernel_to_xstate(kstate, ustate);
+       ret = copy_uabi_from_kernel_to_xstate(kstate, ustate, vpkru);
        if (ret)
                return ret;
 

diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c
index 75ffaef..6d056b6 100644 (file)
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -167,7 +167,7 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
        }
 
        fpu_force_restore(fpu);
-       ret = copy_uabi_from_kernel_to_xstate(fpu->fpstate, kbuf ?: tmpbuf);
+       ret = copy_uabi_from_kernel_to_xstate(fpu->fpstate, kbuf ?: tmpbuf, &target->thread.pkru);
 
 out:
        vfree(tmpbuf);

diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index c88c60b..d6f414a 100644 (file)
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1268,7 +1268,7 @@ static int copy_uabi_to_xstate(struct fpstate *fpstate, const void *kbuf,
  * Convert from a ptrace standard-format kernel buffer to kernel XSAVE[S]
  * format and copy to the target thread. Used by ptrace and KVM.
  */
-int copy_uabi_from_kernel_to_xstate(struct fpstate *fpstate, const void *kbuf)
+int copy_uabi_from_kernel_to_xstate(struct fpstate *fpstate, const void *kbuf, u32 *pkru)
 {
        return copy_uabi_to_xstate(fpstate, kbuf, NULL);
 }

diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h
index f08ee27..a4ecb04 100644 (file)
--- a/arch/x86/kernel/fpu/xstate.h
+++ b/arch/x86/kernel/fpu/xstate.h
@@ -46,7 +46,7 @@ extern void __copy_xstate_to_uabi_buf(struct membuf to, struct fpstate *fpstate,
                                      u32 pkru_val, enum xstate_copy_mode copy_mode);
 extern void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk,
                                    enum xstate_copy_mode mode);
-extern int copy_uabi_from_kernel_to_xstate(struct fpstate *fpstate, const void *kbuf);
+extern int copy_uabi_from_kernel_to_xstate(struct fpstate *fpstate, const void *kbuf, u32 *pkru);
 extern int copy_sigframe_from_user_to_xstate(struct task_struct *tsk, const void __user *ubuf);