Commit 11ac16a4 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

KVM: arm64: Simplify PtrAuth alternative patching 



We currently decide to execute the PtrAuth save/restore code based
on a set of branches that evaluate as (ARM64_HAS_ADDRESS_AUTH_ARCH ||
ARM64_HAS_ADDRESS_AUTH_IMP_DEF). This can be easily replaced by
a much simpler test as the ARM64_HAS_ADDRESS_AUTH capability is
exactly this expression.

Suggested-by: default avatarMark Rutland <mark.rutland@arm.com>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 655169ce

arch/arm64/include/asm/kvm_ptrauth.h

+11 −19
Original line number Diff line number Diff line
@@ -61,44 +61,36 @@ 


/*

 * Both ptrauth_switch_to_guest and ptrauth_switch_to_host macros will

 * check for the presence of one of the cpufeature flag

 * ARM64_HAS_ADDRESS_AUTH_ARCH or ARM64_HAS_ADDRESS_AUTH_IMP_DEF and

 * check for the presence ARM64_HAS_ADDRESS_AUTH, which is defined as

 * (ARM64_HAS_ADDRESS_AUTH_ARCH || ARM64_HAS_ADDRESS_AUTH_IMP_DEF) and

 * then proceed ahead with the save/restore of Pointer Authentication

 * key registers.

 * key registers if enabled for the guest.

 */

.macro ptrauth_switch_to_guest g_ctxt, reg1, reg2, reg3

alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH

	b	1000f

alternative_if_not ARM64_HAS_ADDRESS_AUTH

	b	.L__skip_switch\@

alternative_else_nop_endif

alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF

	b	1001f

alternative_else_nop_endif

1000:

	mrs	\reg1, hcr_el2

	and	\reg1, \reg1, #(HCR_API | HCR_APK)

	cbz	\reg1, 1001f

	cbz	\reg1, .L__skip_switch\@

	add	\reg1, \g_ctxt, #CPU_APIAKEYLO_EL1

	ptrauth_restore_state	\reg1, \reg2, \reg3

1001:

.L__skip_switch\@:

.endm



.macro ptrauth_switch_to_host g_ctxt, h_ctxt, reg1, reg2, reg3

alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH

	b	2000f

alternative_else_nop_endif

alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF

	b	2001f

alternative_if_not ARM64_HAS_ADDRESS_AUTH

	b	.L__skip_switch\@

alternative_else_nop_endif

2000:

	mrs	\reg1, hcr_el2

	and	\reg1, \reg1, #(HCR_API | HCR_APK)

	cbz	\reg1, 2001f

	cbz	\reg1, .L__skip_switch\@

	add	\reg1, \g_ctxt, #CPU_APIAKEYLO_EL1

	ptrauth_save_state	\reg1, \reg2, \reg3

	add	\reg1, \h_ctxt, #CPU_APIAKEYLO_EL1

	ptrauth_restore_state	\reg1, \reg2, \reg3

	isb

2001:

.L__skip_switch\@:

.endm



#else /* !CONFIG_ARM64_PTR_AUTH */