On 5/8/2024 7:17 AM, Dave Hansen wrote:
On 5/7/24 15:57, Sean Christopherson wrote:
[...]
My one request would be to change the WARN in os_xsave() to fire on CET_KERNEL,
not KERNEL_DYNAMIC, because it's specifically CET_KERNEL that is guest-only.
Future dynamic xfeatures could be guest-only, but they could also be dynamic for
some completely different reason. That was my other hang-up with "DYNAMIC";
as-is, os_xsave() implies that it really truly is GUEST_ONLY.
diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h
index 83ebf1e1cbb4..2a1ff49ccfd5 100644
--- a/arch/x86/kernel/fpu/xstate.h
+++ b/arch/x86/kernel/fpu/xstate.h
@@ -185,8 +185,7 @@ static inline void os_xsave(struct fpstate *fpstate)
WARN_ON_FPU(!alternatives_patched);
xfd_validate_state(fpstate, mask, false);
- WARN_ON_FPU(!fpstate->is_guest &&
- (mask & XFEATURE_MASK_KERNEL_DYNAMIC));
+ WARN_ON_FPU(!fpstate->is_guest && (mask & XFEATURE_MASK_CET_KERNEL));
XSTATE_XSAVE(&fpstate->regs.xsave, lmask, hmask, err);
Yeah, that would make a lot of sense. We could add a more generic
#define for it later if another feature gets added like this.
Thank you for getting alignment! I will change the code accordingly.
