Commit 97cbd2fc authored by David Brazdil's avatar David Brazdil Committed by Marc Zyngier
Browse files

KVM: arm64: Fix constant-pool users in hyp 



Hyp code uses absolute addressing to obtain a kimg VA of a small number
of kernel symbols. Since the kernel now converts constant pool addresses
to hyp VAs, this trick does not work anymore.

Change the helpers to convert from hyp VA back to kimg VA or PA, as
needed and rework the callers accordingly.

Signed-off-by: default avatarDavid Brazdil <dbrazdil@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210105180541.65031-7-dbrazdil@google.com
parent 6ec6259d

arch/arm64/include/asm/kvm_mmu.h

+16 −26
Original line number Diff line number Diff line
@@ -73,49 +73,39 @@ alternative_cb_end 
.endm



/*

 * Convert a kernel image address to a PA

 * reg: kernel address to be converted in place

 * Convert a hypervisor VA to a PA

 * reg: hypervisor 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_get_kimage_voffset uses the

 * specific registers encoded in the instructions).

 */

.macro kimg_pa reg, tmp

alternative_cb kvm_get_kimage_voffset

	movz	\tmp, #0

	movk	\tmp, #0, lsl #16

	movk	\tmp, #0, lsl #32

	movk	\tmp, #0, lsl #48

alternative_cb_end



	/* reg = __pa(reg) */

	sub	\reg, \reg, \tmp

.macro hyp_pa reg, tmp

	ldr_l	\tmp, hyp_physvirt_offset

	add	\reg, \reg, \tmp

.endm



/*

 * Convert a kernel image address to a hyp VA

 * reg: kernel address to be converted in place

 * Convert a hypervisor VA to a kernel image address

 * reg: hypervisor 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

 * perform the register allocation (kvm_get_kimage_voffset uses the

 * specific registers encoded in the instructions).

 */

.macro kimg_hyp_va reg, tmp

alternative_cb kvm_update_kimg_phys_offset

.macro hyp_kimg_va reg, tmp

	/* Convert hyp VA -> PA. */

	hyp_pa	\reg, \tmp



	/* Load kimage_voffset. */

alternative_cb kvm_get_kimage_voffset

	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

	/* Convert PA -> kimg VA. */

	add	\reg, \reg, \tmp

.endm



#else

arch/arm64/kvm/hyp/nvhe/host.S

+15 −14
Original line number Diff line number Diff line
@@ -74,27 +74,28 @@ SYM_FUNC_END(__host_enter) 
 * void __noreturn __hyp_do_panic(bool restore_host, u64 spsr, u64 elr, u64 par);

 */

SYM_FUNC_START(__hyp_do_panic)

	/* Load the format arguments into x1-7 */

	mov	x6, x3

	get_vcpu_ptr x7, x3



	mrs	x3, esr_el2

	mrs	x4, far_el2

	mrs	x5, hpfar_el2



	/* Prepare and exit to the host's panic funciton. */

	mov	lr, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT |\

		      PSR_MODE_EL1h)

	msr	spsr_el2, lr

	ldr	lr, =panic

	hyp_kimg_va lr, x6

	msr	elr_el2, lr



	/*

	 * Set the panic format string and enter the host, conditionally

	 * restoring the host context.

	 */

	/* Set the panic format string. Use the, now free, LR as scratch. */

	ldr	lr, =__hyp_panic_string

	hyp_kimg_va lr, x6



	/* Load the format arguments into x1-7. */

	mov	x6, x3

	get_vcpu_ptr x7, x3

	mrs	x3, esr_el2

	mrs	x4, far_el2

	mrs	x5, hpfar_el2



	/* Enter the host, conditionally restoring the host context. */

	cmp	x0, xzr

	ldr	x0, =__hyp_panic_string

	mov	x0, lr

	b.eq	__host_enter_without_restoring

	b	__host_enter_for_panic

SYM_FUNC_END(__hyp_do_panic)
@@ -124,7 +125,7 @@ SYM_FUNC_END(__hyp_do_panic) 
	 * Preserve x0-x4, which may contain stub parameters.

	 */

	ldr	x5, =__kvm_handle_stub_hvc

	kimg_pa x5, x6

	hyp_pa	x5, x6

	br	x5

.L__vect_end\@:

.if ((.L__vect_end\@ - .L__vect_start\@) > 0x80)

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

+0 −2
Original line number Diff line number Diff line
@@ -139,7 +139,6 @@ alternative_else_nop_endif 


	/* Set the host vector */

	ldr	x0, =__kvm_hyp_host_vector

	kimg_hyp_va x0, x1

	msr	vbar_el2, x0



	ret
@@ -198,7 +197,6 @@ SYM_CODE_START_LOCAL(__kvm_hyp_init_cpu) 
	/* Leave idmap. */

	mov	x0, x29

	ldr	x1, =kvm_host_psci_cpu_entry

	kimg_hyp_va x1, x2

	br	x1

SYM_CODE_END(__kvm_hyp_init_cpu)