[PATCH v3 15/41] KVM: arm64: Remove kern_hyp_va() use in VHE switch function

On Wed, Jan 24, 2018 at 04:24:15PM +0000, Dave Martin wrote:

On Fri, Jan 12, 2018 at 01:07:21PM +0100, Christoffer Dall wrote:

quoted

VHE kernels run completely in EL2 and therefore don't have a notion of
kernel and hyp addresses, they are all just kernel addresses.  Therefore
don't call kern_hyp_va() in the VHE switch function.

Isn't this an example of avoidable forkage?

This looks like it's probably just saving a couple of nops, though I may
have misunderstood how this interfacts with alternatives.

In isolation, and if we stopped here, you're absolutely right, it
doesn't make sense.  But this is just a step on the way to significantly
reduce the _vhe version.  Have a look at the following patches and the
end result and let me know if you still have concerns.

Thanks,
-Christoffer

quoted

Reviewed-by: Andrew Jones <redacted>
Reviewed-by: Marc Zyngier <redacted>
Signed-off-by: Christoffer Dall <redacted>
---
 arch/arm64/kvm/hyp/switch.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index accfe9a016f9..05fba76ec918 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c

@@ -345,9 +345,7 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
 	struct kvm_cpu_context *guest_ctxt;
 	u64 exit_code;
 
-	vcpu = kern_hyp_va(vcpu);
-
-	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
+	host_ctxt = vcpu->arch.host_cpu_context;
 	host_ctxt->__hyp_running_vcpu = vcpu;
 	guest_ctxt = &vcpu->arch.ctxt;
 

-- 
2.14.2

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