arm64: KVM: Optimize arm64 skip 30-50% vfp/simd save/restore on exits
This patch only saves and restores FP/SIMD registers on Guest access. To do
this cptr_el2 FP/SIMD trap is set on Guest entry and later checked on exit.
lmbench, hackbench show significant improvements, for 30-50% exits FP/SIMD
context is not saved/restored
[chazy/maz: fixed save/restore logic for 32bit guests]
Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index ac6fafb..7605e09 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -171,10 +171,13 @@
#define HSTR_EL2_TTEE (1 << 16)
#define HSTR_EL2_T(x) (1 << x)
+/* Hyp Coproccessor Trap Register Shifts */
+#define CPTR_EL2_TFP_SHIFT 10
+
/* Hyp Coprocessor Trap Register */
#define CPTR_EL2_TCPAC (1 << 31)
#define CPTR_EL2_TTA (1 << 20)
-#define CPTR_EL2_TFP (1 << 10)
+#define CPTR_EL2_TFP (1 << CPTR_EL2_TFP_SHIFT)
/* Hyp Debug Configuration Register bits */
#define MDCR_EL2_TDRA (1 << 11)