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arm64: KVM: Simplify HYP init/teardown

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Now that we only have the "merged page tables" case to deal with,
there is a bunch of things we can simplify in the HYP code (both
at init and teardown time).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
This commit is contained in:
Marc Zyngier
2016-06-30 18:40:44 +01:00
committed by Christoffer Dall
parent 0535a3e2b2
commit 3421e9d88d
5 changed files with 26 additions and 92 deletions
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61
arch/arm64/kvm/hyp-init.S
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@@ -53,10 +53,9 @@ __invalid:
b .
/*
* x0: HYP boot pgd
* x1: HYP pgd
* x2: HYP stack
* x3: HYP vectors
* x0: HYP pgd
* x1: HYP stack
* x2: HYP vectors
*/
__do_hyp_init:
@@ -110,71 +109,27 @@ __do_hyp_init:
msr sctlr_el2, x4
isb
/* Skip the trampoline dance if we merged the boot and runtime PGDs */
cmp x0, x1
b.eq merged
/* MMU is now enabled. Get ready for the trampoline dance */
ldr x4, =TRAMPOLINE_VA
adr x5, target
bfi x4, x5, #0, #PAGE_SHIFT
br x4
target: /* We're now in the trampoline code, switch page tables */
msr ttbr0_el2, x1
isb
/* Invalidate the old TLBs */
tlbi alle2
dsb sy
merged:
/* Set the stack and new vectors */
kern_hyp_va x1
mov sp, x1
kern_hyp_va x2
mov sp, x2
kern_hyp_va x3
msr vbar_el2, x3
msr vbar_el2, x2
/* Hello, World! */
eret
ENDPROC(__kvm_hyp_init)
/*
* Reset kvm back to the hyp stub. This is the trampoline dance in
* reverse. If kvm used an extended idmap, __extended_idmap_trampoline
* calls this code directly in the idmap. In this case switching to the
* boot tables is a no-op.
*
* x0: HYP boot pgd
* x1: HYP phys_idmap_start
* Reset kvm back to the hyp stub.
*/
ENTRY(__kvm_hyp_reset)
/* We're in trampoline code in VA, switch back to boot page tables */
msr ttbr0_el2, x0
isb
/* Ensure the PA branch doesn't find a stale tlb entry or stale code. */
ic iallu
tlbi alle2
dsb sy
isb
/* Branch into PA space */
adr x0, 1f
bfi x1, x0, #0, #PAGE_SHIFT
br x1
/* We're now in idmap, disable MMU */
1: mrs x0, sctlr_el2
mrs x0, sctlr_el2
ldr x1, =SCTLR_ELx_FLAGS
bic x0, x0, x1 // Clear SCTL_M and etc
msr sctlr_el2, x0
isb
/* Invalidate the old TLBs */
tlbi alle2
dsb sy
/* Install stub vectors */
adr_l x0, __hyp_stub_vectors
msr vbar_el2, x0