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Commit d68c1f7f authored by Marc Zyngier's avatar Marc Zyngier Committed by Christoffer Dall
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arm64: KVM: Preserve RES1 bits in SCTLR_EL2 



__do_hyp_init has the rather bad habit of ignoring RES1 bits and
writing them back as zero. On a v8.0-8.2 CPU, this doesn't do anything
bad, but may end-up being pretty nasty on future revisions of the
architecture.

Let's preserve those bits so that we don't have to fix this later on.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarChristoffer Dall <cdall@linaro.org>
parent d6dbdd3c

arch/arm64/include/asm/sysreg.h

+4 −0
Original line number Diff line number Diff line
@@ -286,6 +286,10 @@ 
#define SCTLR_ELx_A	(1 << 1)

#define SCTLR_ELx_M	1



#define SCTLR_EL2_RES1	((1 << 4)  | (1 << 5)  | (1 << 11) | (1 << 16) | \

			 (1 << 16) | (1 << 18) | (1 << 22) | (1 << 23) | \

			 (1 << 28) | (1 << 29))



#define SCTLR_ELx_FLAGS	(SCTLR_ELx_M | SCTLR_ELx_A | SCTLR_ELx_C | \

			 SCTLR_ELx_SA | SCTLR_ELx_I)

arch/arm64/kvm/hyp-init.S

+6 −4
Original line number Diff line number Diff line
@@ -106,10 +106,12 @@ __do_hyp_init: 
	tlbi	alle2

	dsb	sy



	mrs	x4, sctlr_el2

	and	x4, x4, #SCTLR_ELx_EE	// preserve endianness of EL2

	ldr	x5, =SCTLR_ELx_FLAGS

	orr	x4, x4, x5

	/*

	 * Preserve all the RES1 bits while setting the default flags,

	 * as well as the EE bit on BE.

	 */

	ldr	x4, =(SCTLR_EL2_RES1 | SCTLR_ELx_FLAGS)

CPU_BE(	orr	x4, x4, #SCTLR_ELx_EE)

	msr	sctlr_el2, x4

	isb