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Subject[PATCH] arm64: KVM: Skip PSTATE.PAN reest at EL2 in non-VHE
Date
PSTATE.PAN disables reading and/or writing to a userspace virtual
address from EL1 in non-VHE or from EL2 in VHE. In non-VHE, there is
no any userspace mapping at EL2, so no need to reest the PSTATE.PAN.

Signed-off-by: Dongjiu Geng <gengdongjiu@huawei.com>
Signed-off-by: Haibin Zhang <zhanghaibin7@huawei.com>
---
arch/arm64/kvm/hyp/entry.S | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index 12ee62d6d410..86a7549b1b4c 100644
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -96,8 +96,12 @@ ENTRY(__guest_exit)

add x1, x1, #VCPU_CONTEXT

- ALTERNATIVE(nop, SET_PSTATE_PAN(1), ARM64_HAS_PAN, CONFIG_ARM64_PAN)
+alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
+ b 2f // skip PAN at EL2 in non-VHE
+alternative_else_nop_endif

+ ALTERNATIVE(nop, SET_PSTATE_PAN(1), ARM64_HAS_PAN, CONFIG_ARM64_PAN)
+2:
// Store the guest regs x2 and x3
stp x2, x3, [x1, #CPU_XREG_OFFSET(2)]

--
2.14.1
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