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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: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
This commit is contained in:
Marc Zyngier 2017-06-06 19:08:33 +01:00 committed by Christoffer Dall
parent d6dbdd3c85
commit d68c1f7fd1
2 changed files with 10 additions and 4 deletions
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4
arch/arm64/include/asm/sysreg.h
View File

@ -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)

10
arch/arm64/kvm/hyp-init.S
View File

@ -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