arm64: KVM: Preserve RES1 bits in SCTLR_EL2
commit d68c1f7fd1b7148dab5fe658321d511998969f2d upstream.
__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.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 6b29d3d..4e460d9 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -102,10 +102,12 @@
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