Commit 5be1d622 authored by David Brazdil's avatar David Brazdil Committed by Marc Zyngier
Browse files

KVM: arm64: Remove vector_ptr param of hyp-init 



KVM precomputes the hyp VA of __kvm_hyp_host_vector, essentially a
constant (minus ASLR), before passing it to __kvm_hyp_init.
Now that we have alternatives for converting kimg VA to hyp VA, replace
this with computing the constant inside __kvm_hyp_init, thus removing
the need for an argument.

Signed-off-by: default avatarDavid Brazdil <dbrazdil@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-10-dbrazdil@google.com
parent 78869f0f

arch/arm64/include/asm/kvm_asm.h

+0 −2
Original line number Diff line number Diff line
@@ -165,10 +165,8 @@ struct kvm_vcpu; 
struct kvm_s2_mmu;



DECLARE_KVM_NVHE_SYM(__kvm_hyp_init);

DECLARE_KVM_NVHE_SYM(__kvm_hyp_host_vector);

DECLARE_KVM_HYP_SYM(__kvm_hyp_vector);

#define __kvm_hyp_init		CHOOSE_NVHE_SYM(__kvm_hyp_init)

#define __kvm_hyp_host_vector	CHOOSE_NVHE_SYM(__kvm_hyp_host_vector)

#define __kvm_hyp_vector	CHOOSE_HYP_SYM(__kvm_hyp_vector)



extern unsigned long kvm_arm_hyp_percpu_base[NR_CPUS];

arch/arm64/include/asm/kvm_mmu.h

+24 −0
Original line number Diff line number Diff line
@@ -94,6 +94,30 @@ alternative_cb_end 
	sub	\reg, \reg, \tmp

.endm



/*

 * Convert a kernel image address to a hyp VA

 * reg: kernel address to be converted in place

 * tmp: temporary register

 *

 * The actual code generation takes place in kvm_get_kimage_voffset, and

 * the instructions below are only there to reserve the space and

 * perform the register allocation (kvm_update_kimg_phys_offset uses the

 * specific registers encoded in the instructions).

 */

.macro kimg_hyp_va reg, tmp

alternative_cb kvm_update_kimg_phys_offset

	movz	\tmp, #0

	movk	\tmp, #0, lsl #16

	movk	\tmp, #0, lsl #32

	movk	\tmp, #0, lsl #48

alternative_cb_end



	sub	\reg, \reg, \tmp

	mov_q	\tmp, PAGE_OFFSET

	orr	\reg, \reg, \tmp

	kern_hyp_va \reg

.endm



#else



#include <linux/pgtable.h>

arch/arm64/kvm/arm.c

+1 −3
Original line number Diff line number Diff line
@@ -1335,7 +1335,6 @@ static void cpu_init_hyp_mode(void) 
{

	phys_addr_t pgd_ptr;

	unsigned long hyp_stack_ptr;

	unsigned long vector_ptr;

	unsigned long tpidr_el2;

	struct arm_smccc_res res;
@@ -1353,7 +1352,6 @@ static void cpu_init_hyp_mode(void) 
	pgd_ptr = kvm_mmu_get_httbr();

	hyp_stack_ptr = __this_cpu_read(kvm_arm_hyp_stack_page) + PAGE_SIZE;

	hyp_stack_ptr = kern_hyp_va(hyp_stack_ptr);

	vector_ptr = (unsigned long)kern_hyp_va(kvm_ksym_ref(__kvm_hyp_host_vector));



	/*

	 * Call initialization code, and switch to the full blown HYP code.
@@ -1363,7 +1361,7 @@ static void cpu_init_hyp_mode(void) 
	 */

	BUG_ON(!system_capabilities_finalized());

	arm_smccc_1_1_hvc(KVM_HOST_SMCCC_FUNC(__kvm_hyp_init),

			  pgd_ptr, tpidr_el2, hyp_stack_ptr, vector_ptr, &res);

			  pgd_ptr, tpidr_el2, hyp_stack_ptr, &res);

	WARN_ON(res.a0 != SMCCC_RET_SUCCESS);



	/*

arch/arm64/kvm/hyp/nvhe/hyp-init.S

+6 −3
Original line number Diff line number Diff line
@@ -50,7 +50,6 @@ __invalid: 
	 * x1: HYP pgd

	 * x2: per-CPU offset

	 * x3: HYP stack

	 * x4: HYP vectors

	 */

__do_hyp_init:

	/* Check for a stub HVC call */
@@ -134,9 +133,13 @@ alternative_else_nop_endif 
	msr	sctlr_el2, x0

	isb



	/* Set the stack and new vectors */

	/* Set the stack */

	mov	sp, x3

	msr	vbar_el2, x4



	/* Set the host vector */

	ldr	x0, =__kvm_hyp_host_vector

	kimg_hyp_va x0, x1

	msr	vbar_el2, x0



	/* Hello, World! */

	mov	x0, #SMCCC_RET_SUCCESS