[PATCH v3 17/23] arm64: KVM: VHE: Add fpsimd enabling on guest access

Marc Zyngier
2016-02-03T18:00:52Z

Despite the fact that a VHE enabled kernel runs at EL2, it uses
CPACR_EL1 to trap FPSIMD access. Add the required alternative
code to re-enable guest FPSIMD access when it has trapped to
EL2.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm64/kvm/hyp/entry.S | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index fd0fbe9..ce9e5e5 100644
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -130,9 +130,15 @@ ENDPROC(__guest_exit)
ENTRY(__fpsimd_guest_restore)
stp x4, lr, [sp, #-16]!

+alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
mrs x2, cptr_el2
bic x2, x2, #CPTR_EL2_TFP
msr cptr_el2, x2
+alternative_else
+ mrs x2, cpacr_el1
+ orr x2, x2, #CPACR_EL1_FPEN
+ msr cpacr_el1, x2
+alternative_endif
isb

mrs x3, tpidr_el2
--
2.1.4