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.
Reviewed-by: Reiji Watanabe <reijiw@xxxxxxxxxx>
Signed-off-by: Oliver Upton <oupton@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 2 ++
arch/arm64/kvm/sys_regs.c | 31 ++++++++++++++++++++++++-------
2 files changed, 26 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 2a5f7f38006f..53fc8a6eaf1c 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -172,8 +172,10 @@ enum vcpu_sysreg {
PAR_EL1, /* Physical Address Register */
MDSCR_EL1, /* Monitor Debug System Control Register */
MDCCINT_EL1, /* Monitor Debug Comms Channel Interrupt Enable Reg */
+ OSLSR_EL1, /* OS Lock Status Register */
DISR_EL1, /* Deferred Interrupt Status Register */
+
/* Performance Monitors Registers */
PMCR_EL0, /* Control Register */
PMSELR_EL0, /* Event Counter Selection Register */
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 11b4212c2036..7bf350b3d9cd 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -291,12 +291,28 @@ static bool trap_oslsr_el1(struct kvm_vcpu *vcpu,
struct sys_reg_params *p,
const struct sys_reg_desc *r)
{
- if (p->is_write) {
+ if (p->is_write)
return write_to_read_only(vcpu, p, r);
- } else {
- p->regval = (1 << 3);
- return true;
- }
+
+ p->regval = __vcpu_sys_reg(vcpu, r->reg);
+ return true;
+}
+
+static int set_oslsr_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ u64 id = sys_reg_to_index(rd);
+ u64 val;
+ int err;
+
+ err = reg_from_user(&val, uaddr, id);
+ if (err)
+ return err;
+
+ if (val != rd->val)
+ return -EINVAL;
+
+ return 0;
}
static bool trap_dbgauthstatus_el1(struct kvm_vcpu *vcpu,
@@ -1448,7 +1464,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
{ SYS_DESC(SYS_MDRAR_EL1), trap_raz_wi },
{ SYS_DESC(SYS_OSLAR_EL1), trap_raz_wi },
- { SYS_DESC(SYS_OSLSR_EL1), trap_oslsr_el1 },
+ { SYS_DESC(SYS_OSLSR_EL1), trap_oslsr_el1, reset_val, OSLSR_EL1, 0x00000008,
+ .set_user = set_oslsr_el1, },
{ SYS_DESC(SYS_OSDLR_EL1), trap_raz_wi },
{ SYS_DESC(SYS_DBGPRCR_EL1), trap_raz_wi },
{ SYS_DESC(SYS_DBGCLAIMSET_EL1), trap_raz_wi },
@@ -1923,7 +1940,7 @@ static const struct sys_reg_desc cp14_regs[] = {
{ Op1( 0), CRn( 1), CRm( 0), Op2( 4), trap_raz_wi },
DBGBXVR(1),
/* DBGOSLSR */
- { Op1( 0), CRn( 1), CRm( 1), Op2( 4), trap_oslsr_el1 },
+ { Op1( 0), CRn( 1), CRm( 1), Op2( 4), trap_oslsr_el1, NULL, OSLSR_EL1 },
DBGBXVR(2),
DBGBXVR(3),
/* DBGOSDLR */
--
2.34.0.rc2.393.gf8c9666880-goog
