Commit 04e4caa8 authored by Andrew Scull's avatar Andrew Scull Committed by Marc Zyngier
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KVM: arm64: nVHE: Migrate hyp-init to SMCCC 



To complete the transition to SMCCC, the hyp initialization is given a
function ID. This looks neater than comparing the hyp stub function IDs
to the page table physical address.

Some care is taken to only clobber x0-3 before the host context is saved
as only those registers can be clobbered accoring to SMCCC. Fortunately,
only a few acrobatics are needed. The possible new tpidr_el2 is moved to
the argument in x2 so that it can be stashed in tpidr_el2 early to free
up a scratch register. The page table configuration then makes use of
x0-2.

Signed-off-by: default avatarAndrew Scull <ascull@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200915104643.2543892-19-ascull@google.com
parent 05469831

arch/arm64/include/asm/kvm_host.h

+0 −5
Original line number Diff line number Diff line
@@ -480,11 +480,6 @@ int kvm_test_age_hva(struct kvm *kvm, unsigned long hva); 
void kvm_arm_halt_guest(struct kvm *kvm);

void kvm_arm_resume_guest(struct kvm *kvm);



u64 __kvm_call_hyp_init(phys_addr_t pgd_ptr,

			unsigned long hyp_stack_ptr,

			unsigned long vector_ptr,

			unsigned long tpidr_el2);



#define kvm_call_hyp_nvhe(f, ...)						\

	({								\

		struct arm_smccc_res res;				\

arch/arm64/kvm/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -13,7 +13,7 @@ obj-$(CONFIG_KVM) += hyp/ 
kvm-y := $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o \

	 $(KVM)/vfio.o $(KVM)/irqchip.o \

	 arm.o mmu.o mmio.o psci.o perf.o hypercalls.o pvtime.o \

	 inject_fault.o regmap.o va_layout.o hyp.o handle_exit.o \

	 inject_fault.o regmap.o va_layout.o handle_exit.o \

	 guest.o debug.o reset.o sys_regs.o \

	 vgic-sys-reg-v3.o fpsimd.o pmu.o \

	 aarch32.o arch_timer.o \

arch/arm64/kvm/arm.c

+4 −1
Original line number Diff line number Diff line
@@ -1264,6 +1264,7 @@ static void cpu_init_hyp_mode(void) 
	unsigned long hyp_stack_ptr;

	unsigned long vector_ptr;

	unsigned long tpidr_el2;

	struct arm_smccc_res res;



	/* Switch from the HYP stub to our own HYP init vector */

	__hyp_set_vectors(kvm_get_idmap_vector());
@@ -1288,7 +1289,9 @@ static void cpu_init_hyp_mode(void) 
	 * cpus_have_const_cap() wrapper.

	 */

	BUG_ON(!system_capabilities_finalized());

	__kvm_call_hyp_init(pgd_ptr, hyp_stack_ptr, vector_ptr, tpidr_el2);

	arm_smccc_1_1_hvc(KVM_HOST_SMCCC_FUNC(__kvm_hyp_init),

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

	WARN_ON(res.a0 != SMCCC_RET_SUCCESS);



	/*

	 * Disabling SSBD on a non-VHE system requires us to enable SSBS

arch/arm64/kvm/hyp.S

deleted100644 → 0
+0 −22
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0-only */

/*

 * Copyright (C) 2012,2013 - ARM Ltd

 * Author: Marc Zyngier <marc.zyngier@arm.com>

 */



#include <linux/linkage.h>



#include <asm/alternative.h>

#include <asm/assembler.h>

#include <asm/cpufeature.h>



/*

 * u64 __kvm_call_hyp_init(phys_addr_t pgd_ptr,

 * 			   unsigned long hyp_stack_ptr,

 * 			   unsigned long vector_ptr,

 * 			   unsigned long tpidr_el2);

 */

SYM_FUNC_START(__kvm_call_hyp_init)

	hvc	#0

	ret

SYM_FUNC_END(__kvm_call_hyp_init)

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

+38 −28
Original line number Diff line number Diff line
@@ -4,11 +4,13 @@ 
 * Author: Marc Zyngier <marc.zyngier@arm.com>

 */



#include <linux/arm-smccc.h>

#include <linux/linkage.h>



#include <asm/alternative.h>

#include <asm/assembler.h>

#include <asm/kvm_arm.h>

#include <asm/kvm_asm.h>

#include <asm/kvm_mmu.h>

#include <asm/pgtable-hwdef.h>

#include <asm/sysreg.h>
@@ -44,27 +46,37 @@ __invalid: 
	b	.



	/*

	 * x0: HYP pgd

	 * x1: HYP stack

	 * x2: HYP vectors

	 * x3: per-CPU offset

	 * x0: SMCCC function ID

	 * x1: HYP pgd

	 * x2: per-CPU offset

	 * x3: HYP stack

	 * x4: HYP vectors

	 */

__do_hyp_init:

	/* Check for a stub HVC call */

	cmp	x0, #HVC_STUB_HCALL_NR

	b.lo	__kvm_handle_stub_hvc



	phys_to_ttbr x4, x0

	/* Set tpidr_el2 for use by HYP to free a register */

	msr	tpidr_el2, x2



	mov	x2, #KVM_HOST_SMCCC_FUNC(__kvm_hyp_init)

	cmp	x0, x2

	b.eq	1f

	mov	x0, #SMCCC_RET_NOT_SUPPORTED

	eret



1:	phys_to_ttbr x0, x1

alternative_if ARM64_HAS_CNP

	orr	x4, x4, #TTBR_CNP_BIT

	orr	x0, x0, #TTBR_CNP_BIT

alternative_else_nop_endif

	msr	ttbr0_el2, x4

	msr	ttbr0_el2, x0



	mrs	x4, tcr_el1

	mov_q	x5, TCR_EL2_MASK

	and	x4, x4, x5

	mov	x5, #TCR_EL2_RES1

	orr	x4, x4, x5

	mrs	x0, tcr_el1

	mov_q	x1, TCR_EL2_MASK

	and	x0, x0, x1

	mov	x1, #TCR_EL2_RES1

	orr	x0, x0, x1



	/*

	 * The ID map may be configured to use an extended virtual address
@@ -80,18 +92,18 @@ alternative_else_nop_endif 
	 *

	 * So use the same T0SZ value we use for the ID map.

	 */

	ldr_l	x5, idmap_t0sz

	bfi	x4, x5, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH

	ldr_l	x1, idmap_t0sz

	bfi	x0, x1, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH



	/*

	 * Set the PS bits in TCR_EL2.

	 */

	tcr_compute_pa_size x4, #TCR_EL2_PS_SHIFT, x5, x6

	tcr_compute_pa_size x0, #TCR_EL2_PS_SHIFT, x1, x2



	msr	tcr_el2, x4

	msr	tcr_el2, x0



	mrs	x4, mair_el1

	msr	mair_el2, x4

	mrs	x0, mair_el1

	msr	mair_el2, x0

	isb



	/* Invalidate the stale TLBs from Bootloader */
@@ -103,24 +115,22 @@ alternative_else_nop_endif 
	 * as well as the EE bit on BE. Drop the A flag since the compiler

	 * is allowed to generate unaligned accesses.

	 */

	mov_q	x4, (SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A))

CPU_BE(	orr	x4, x4, #SCTLR_ELx_EE)

	mov_q	x0, (SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A))

CPU_BE(	orr	x0, x0, #SCTLR_ELx_EE)

alternative_if ARM64_HAS_ADDRESS_AUTH

	mov_q	x5, (SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | \

	mov_q	x1, (SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | \

		     SCTLR_ELx_ENDA | SCTLR_ELx_ENDB)

	orr	x4, x4, x5

	orr	x0, x0, x1

alternative_else_nop_endif

	msr	sctlr_el2, x4

	msr	sctlr_el2, x0

	isb



	/* Set the stack and new vectors */

	mov	sp, x1

	msr	vbar_el2, x2



	/* Set tpidr_el2 for use by HYP */

	msr	tpidr_el2, x3

	mov	sp, x3

	msr	vbar_el2, x4



	/* Hello, World! */

	mov	x0, #SMCCC_RET_SUCCESS

	eret

SYM_CODE_END(__kvm_hyp_init)

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