On 12/8/21 01:03, Yang Zhong wrote:
+ /*
+ * Update IA32_XFD to the guest value so #NM can be
+ * raised properly in the guest. Instead of directly
+ * writing the MSR, call a helper to avoid breaking
+ * per-cpu cached value in fpu core.
+ */
+ fpregs_lock();
+ current->thread.fpu.fpstate->xfd = data;
This is wrong, it should be written in vcpu->arch.guest_fpu.
+ xfd_update_state(current->thread.fpu.fpstate);
This is okay though, so that KVM_SET_MSR will not write XFD and WRMSR will.
That said, I think xfd_update_state should not have an argument.
current->thread.fpu.fpstate->xfd is the only fpstate that should be
synced with the xfd_state per-CPU variable.
Paolo
+ fpregs_unlock();
