[PATCH V2] ARM/ARM64: KVM: Nuke Hyp-mode tlbs before enabling MMU

[Pranavkumar Sawargaonkar]

X-Gene u-boot runs in EL2 mode with MMU enabled hence we might
have stale EL2 tlb enteris when we enable EL2 MMU on each host CPU.

This can happen on any ARM/ARM64 board running bootloader in
Hyp-mode (or EL2-mode) with MMU enabled.

This patch ensures that we flush all Hyp-mode (or EL2-mode) TLBs
on each host CPU before enabling Hyp-mode (or EL2-mode) MMU.

Changelog:

V2:
 - Flush Hyp-mode TLBs for both KVM ARM32 and KVM ARM64 at boot time

V1:
 - Initial patch with only arm64 change

Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar at linaro.org>
Signed-off-by: Anup Patel <anup.patel at linaro.org>
---
 arch/arm/kvm/init.S       |    4 ++++
 arch/arm64/kvm/hyp-init.S |    4 ++++
 2 files changed, 8 insertions(+)

diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index 1b9844d..ee4f744 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -98,6 +98,10 @@ __do_hyp_init:
 	mrc	p15, 0, r0, c10, c2, 1
 	mcr	p15, 4, r0, c10, c2, 1
 
+	@ Invalidate the stale TLBs from Bootloader
+	mcr	p15, 4, r0, c8, c7, 0	@ TLBIALLH
+	dsb	ish
+
 	@ Set the HSCTLR to:
 	@  - ARM/THUMB exceptions: Kernel config (Thumb-2 kernel)
 	@  - Endianness: Kernel config
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index d968796..c319116 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -80,6 +80,10 @@ __do_hyp_init:
 	msr	mair_el2, x4
 	isb
 
+	/* Invalidate the stale TLBs from Bootloader */
+	tlbi	alle2
+	dsb	sy
+
 	mrs	x4, sctlr_el2
 	and	x4, x4, #SCTLR_EL2_EE	// preserve endianness of EL2
 	ldr	x5, =SCTLR_EL2_FLAGS
-- 
1.7.9.5