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arm: KVM: Simplify HYP init

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Just like for arm64, we can now make the HYP setup a lot simpler,
and we can now initialise it in one go (instead of the two
phases we currently have).

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 18:40:47 +01:00 committed by Christoffer Dall
parent 26781f9ce1
commit cd602a37e8
2 changed files with 14 additions and 50 deletions
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15
arch/arm/include/asm/kvm_host.h
View file

@ -250,18 +250,13 @@ static inline void __cpu_init_hyp_mode(phys_addr_t pgd_ptr,
* code. The init code doesn't need to preserve these
* registers as r0-r3 are already callee saved according to
* the AAPCS.
* Note that we slightly misuse the prototype by casing the
* Note that we slightly misuse the prototype by casting the
* stack pointer to a void *.
*
* We don't have enough registers to perform the full init in
* one go. Install the boot PGD first, and then install the
* runtime PGD, stack pointer and vectors. The PGDs are always
* passed as the third argument, in order to be passed into
* r2-r3 to the init code (yes, this is compliant with the
* PCS!).
*/
kvm_call_hyp(NULL, 0, boot_pgd_ptr);
* The PGDs are always passed as the third argument, in order
* to be passed into r2-r3 to the init code (yes, this is
* compliant with the PCS!).
*/
kvm_call_hyp((void*)hyp_stack_ptr, vector_ptr, pgd_ptr);
}

49
arch/arm/kvm/init.S
View file

@ -32,23 +32,13 @@
* r2,r3 = Hypervisor pgd pointer
*
* The init scenario is:
* - We jump in HYP with four parameters: boot HYP pgd, runtime HYP pgd,
* runtime stack, runtime vectors
* - Enable the MMU with the boot pgd
* - Jump to a target into the trampoline page (remember, this is the same
* physical page!)
* - Now switch to the runtime pgd (same VA, and still the same physical
* page!)
* - We jump in HYP with 3 parameters: runtime HYP pgd, runtime stack,
* runtime vectors
* - Invalidate TLBs
* - Set stack and vectors
* - Setup the page tables
* - Enable the MMU
* - Profit! (or eret, if you only care about the code).
*
* As we only have four registers available to pass parameters (and we
* need six), we split the init in two phases:
* - Phase 1: r0 = 0, r1 = 0, r2,r3 contain the boot PGD.
* Provides the basic HYP init, and enable the MMU.
* - Phase 2: r0 = ToS, r1 = vectors, r2,r3 contain the runtime PGD.
* Switches to the runtime PGD, set stack and vectors.
*/
.text
@ -68,8 +58,11 @@ __kvm_hyp_init:
W(b) .
__do_hyp_init:
cmp r0, #0 @ We have a SP?
bne phase2 @ Yes, second stage init
@ Set stack pointer
mov sp, r0
@ Set HVBAR to point to the HYP vectors
mcr p15, 4, r1, c12, c0, 0 @ HVBAR
@ Set the HTTBR to point to the hypervisor PGD pointer passed
mcrr p15, 4, rr_lo_hi(r2, r3), c2
@ -114,33 +107,9 @@ __do_hyp_init:
THUMB( ldr r2, =(HSCTLR_M | HSCTLR_A | HSCTLR_TE) )
orr r1, r1, r2
orr r0, r0, r1
isb
mcr p15, 4, r0, c1, c0, 0 @ HSCR
@ End of init phase-1
eret
phase2:
@ Set stack pointer
mov sp, r0
@ Set HVBAR to point to the HYP vectors
mcr p15, 4, r1, c12, c0, 0 @ HVBAR
@ Jump to the trampoline page
ldr r0, =TRAMPOLINE_VA
adr r1, target
bfi r0, r1, #0, #PAGE_SHIFT
ret r0
target: @ We're now in the trampoline code, switch page tables
mcrr p15, 4, rr_lo_hi(r2, r3), c2
isb
@ Invalidate the old TLBs
mcr p15, 4, r0, c8, c7, 0 @ TLBIALLH
dsb ish
eret
.ltorg