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Commit cd602a37 authored by Marc Zyngier's avatar Marc Zyngier Committed by Christoffer Dall
Browse files

arm: KVM: Simplify HYP init 



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: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
parent 26781f9c

arch/arm/include/asm/kvm_host.h

+5 −10
Original line number Diff line number Diff line
@@ -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);

}

arch/arm/kvm/init.S

+9 −40
Original line number Diff line number Diff line
@@ -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