x86/fpu: Move KVMs FPU swapping to FPU core
Swapping the host/guest FPU is directly fiddling with FPU internals which
requires 5 exports. The upcoming support of dynamically enabled states
would even need more.
Implement a swap function in the FPU core code and export that instead.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org
Link: https://lkml.kernel.org/r/20211015011539.076072399@linutronix.de
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 74712e5..66eea4e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -68,7 +68,9 @@
#include <asm/mce.h>
#include <asm/pkru.h>
#include <linux/kernel_stat.h>
-#include <asm/fpu/internal.h> /* Ugh! */
+#include <asm/fpu/api.h>
+#include <asm/fpu/xcr.h>
+#include <asm/fpu/xstate.h>
#include <asm/pvclock.h>
#include <asm/div64.h>
#include <asm/irq_remapping.h>
@@ -9913,58 +9915,27 @@ static int complete_emulated_mmio(struct kvm_vcpu *vcpu)
return 0;
}
-static void kvm_save_current_fpu(struct fpu *fpu)
-{
- /*
- * If the target FPU state is not resident in the CPU registers, just
- * memcpy() from current, else save CPU state directly to the target.
- */
- if (test_thread_flag(TIF_NEED_FPU_LOAD))
- memcpy(&fpu->state, ¤t->thread.fpu.state,
- fpu_kernel_xstate_size);
- else
- save_fpregs_to_fpstate(fpu);
-}
-
/* Swap (qemu) user FPU context for the guest FPU context. */
static void kvm_load_guest_fpu(struct kvm_vcpu *vcpu)
{
- fpregs_lock();
-
- kvm_save_current_fpu(vcpu->arch.user_fpu);
-
/*
- * Guests with protected state can't have it set by the hypervisor,
- * so skip trying to set it.
+ * Guests with protected state have guest_fpu == NULL which makes
+ * the swap only save the host state. Exclude PKRU from restore as
+ * it is restored separately in kvm_x86_ops.run().
*/
- if (vcpu->arch.guest_fpu)
- /* PKRU is separately restored in kvm_x86_ops.run. */
- __restore_fpregs_from_fpstate(&vcpu->arch.guest_fpu->state,
- ~XFEATURE_MASK_PKRU);
-
- fpregs_mark_activate();
- fpregs_unlock();
-
+ fpu_swap_kvm_fpu(vcpu->arch.user_fpu, vcpu->arch.guest_fpu,
+ ~XFEATURE_MASK_PKRU);
trace_kvm_fpu(1);
}
/* When vcpu_run ends, restore user space FPU context. */
static void kvm_put_guest_fpu(struct kvm_vcpu *vcpu)
{
- fpregs_lock();
-
/*
- * Guests with protected state can't have it read by the hypervisor,
- * so skip trying to save it.
+ * Guests with protected state have guest_fpu == NULL which makes
+ * swap only restore the host state.
*/
- if (vcpu->arch.guest_fpu)
- kvm_save_current_fpu(vcpu->arch.guest_fpu);
-
- restore_fpregs_from_fpstate(&vcpu->arch.user_fpu->state);
-
- fpregs_mark_activate();
- fpregs_unlock();
-
+ fpu_swap_kvm_fpu(vcpu->arch.guest_fpu, vcpu->arch.user_fpu, ~0ULL);
++vcpu->stat.fpu_reload;
trace_kvm_fpu(0);
}