Re: [PATCH] ARM64: KVM: Nuke EL2 mode tlbs before enabling MMU for EL2

[Pranavkumar Sawargaonkar <pranavkumar@xxxxxxxxxx>]

On 30 July 2014 15:16, Pranavkumar Sawargaonkar <pranavkumar@xxxxxxxxxx> wrote:

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 ARM64 board running bootloader in EL2
with MMU enabled.

This patch ensures that we flush all EL2 TLBs on each host CPU
before enabling EL2 MMU. This is very similar to what we do
for EL1 TLBs before enabling EL1 MMU.
(Refer __cpu_setup() of arch/arm64/mm/proc.S)

Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@xxxxxxxxxx>
Signed-off-by: Anup Patel <anup.patel@xxxxxxxxxx>
---
 arch/arm64/kvm/hyp-init.S |    4 ++++
 1 file changed, 4 insertions(+)

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

 

Correcting patches@apm mail id

Thanks,

Pranav

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