Re: [PATCH v2 2/6] KVM: arm64: Stash OSLSR_EL1 in the cpu context

An upcoming change to KVM will context switch the OS Lock status between
guest/host. Add OSLSR_EL1 to the cpu context and handle guest reads
using the stored value.

Wire up a custom handler for writes from userspace and prevent any of
the invariant bits from changing.

Signed-off-by: Oliver Upton <redacted>
---
 arch/arm64/include/asm/kvm_host.h |  1 +
 arch/arm64/kvm/sys_regs.c         | 31 ++++++++++++++++++++++++-------
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index f8be56d5342b..c98f65c4a1f7 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h

@@ -172,6 +172,7 @@ enum vcpu_sysreg {
        MDSCR_EL1,      /* Monitor Debug System Control Register */
        MDCCINT_EL1,    /* Monitor Debug Comms Channel Interrupt Enable Reg */
        DISR_EL1,       /* Deferred Interrupt Status Register */
+       OSLSR_EL1,      /* OS Lock Status Register */