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Commit fa81b25a authored by Andrew Scull's avatar Andrew Scull Committed by Greg Kroah-Hartman
Browse files

KVM: arm64: Stop clobbering x0 for HVC_SOFT_RESTART 



commit b9e10d4a6c9f5cbe6369ce2c17ebc67d2e5a4be5 upstream.

HVC_SOFT_RESTART is given values for x0-2 that it should installed
before exiting to the new address so should not set x0 to stub HVC
success or failure code.

Fixes: af42f204 ("arm64: hyp-stub: Zero x0 on successful stub handling")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarAndrew Scull <ascull@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200706095259.1338221-1-ascull@google.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 27ce7d1c

arch/arm64/kvm/hyp-init.S

+7 −4
Original line number Original line Diff line number Diff line
@@ -144,11 +144,15 @@ ENTRY(__kvm_handle_stub_hvc) 




1:	cmp	x0, #HVC_RESET_VECTORS

1:	cmp	x0, #HVC_RESET_VECTORS

	b.ne	1f

	b.ne	1f

reset:



	/*

	/*

	 * Reset kvm back to the hyp stub. Do not clobber x0-x4 in

	 * Set the HVC_RESET_VECTORS return code before entering the common

	 * case we coming via HVC_SOFT_RESTART.

	 * path so that we do not clobber x0-x2 in case we are coming via

	 * HVC_SOFT_RESTART.

	 */

	 */

	mov	x0, xzr

reset:

	/* Reset kvm back to the hyp stub. */

	mrs	x5, sctlr_el2

	mrs	x5, sctlr_el2

	ldr	x6, =SCTLR_ELx_FLAGS

	ldr	x6, =SCTLR_ELx_FLAGS

	bic	x5, x5, x6		// Clear SCTL_M and etc

	bic	x5, x5, x6		// Clear SCTL_M and etc
@@ -159,7 +163,6 @@ reset: 
	/* Install stub vectors */

	/* Install stub vectors */

	adr_l	x5, __hyp_stub_vectors

	adr_l	x5, __hyp_stub_vectors

	msr	vbar_el2, x5

	msr	vbar_el2, x5

	mov	x0, xzr

	eret

	eret





1:	/* Bad stub call */

1:	/* Bad stub call */