[PATCH v3 06/17] arm64: Allow EL1 physical timer access when running VHE

Marc Zyngier
2023-06-09T16:22:23Z

To initialise the timer access from EL2 when HCR_EL2.E2H is set,
we must make use the CNTHCTL_EL2 formap used is appropriate.

This amounts to shifting the timer/counter enable bits by 10
to the left.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/include/asm/el2_setup.h | 5 +++++
arch/arm64/kvm/hyp/nvhe/hyp-init.S | 9 +++++++++
2 files changed, 14 insertions(+)

diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h
index 037724b19c5c..225bf1f2514d 100644
--- a/arch/arm64/include/asm/el2_setup.h
+++ b/arch/arm64/include/asm/el2_setup.h
@@ -34,6 +34,11 @@
*/
.macro __init_el2_timers
mov x0, #3 // Enable EL1 physical timers
+ mrs x1, hcr_el2
+ and x1, x1, #HCR_E2H
+ cbz x1, .LnVHE_\@
+ lsl x0, x0, #10
+.LnVHE_\@:
msr cnthctl_el2, x0
msr cntvoff_el2, xzr // Clear virtual offset
.endm
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
index a6d67c2bb5ae..f9ee10e29497 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
@@ -95,6 +95,15 @@ SYM_CODE_START_LOCAL(___kvm_hyp_init)
ldr x1, [x0, #NVHE_INIT_HCR_EL2]
msr hcr_el2, x1

+ mov x2, #HCR_E2H
+ and x2, x1, x2
+ cbz x2, 1f
+
+ mrs x1, cnthctl_el2
+ and x1, x1, #~(BIT(0) | BIT(1))
+ orr x1, x1, #(BIT(10) | BIT(11))
+ msr cnthctl_el2, x1
+1:
ldr x1, [x0, #NVHE_INIT_VTTBR]
msr vttbr_el2, x1

--
2.34.1