arm64: KVM: flush VM pages before letting the guest enable caches
authorMarc Zyngier <marc.zyngier@arm.com>
Wed, 15 Jan 2014 12:50:23 +0000 (12:50 +0000)
committerMarc Zyngier <marc.zyngier@arm.com>
Mon, 3 Mar 2014 01:15:22 +0000 (01:15 +0000)
commit9d218a1fcf4c6b759d442ef702842fae92e1ea61
tree1d94bc1753a84945ef1d31c4e162c660829c2875
parenta3c8bd31af260a17d626514f636849ee1cd1f63e
arm64: KVM: flush VM pages before letting the guest enable caches

When the guest runs with caches disabled (like in an early boot
sequence, for example), all the writes are diectly going to RAM,
bypassing the caches altogether.

Once the MMU and caches are enabled, whatever sits in the cache
becomes suddenly visible, which isn't what the guest expects.

A way to avoid this potential disaster is to invalidate the cache
when the MMU is being turned on. For this, we hook into the SCTLR_EL1
trapping code, and scan the stage-2 page tables, invalidating the
pages/sections that have already been mapped in.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
arch/arm/include/asm/kvm_mmu.h
arch/arm/kvm/mmu.c
arch/arm64/include/asm/kvm_mmu.h
arch/arm64/kvm/sys_regs.c