Allow writes to OSLAR and forward the OSLK bit to OSLSR. Do nothing with
the value for now.
Reviewed-by: Reiji Watanabe <reijiw@xxxxxxxxxx>
Signed-off-by: Oliver Upton <oupton@xxxxxxxxxx>
---
arch/arm64/include/asm/sysreg.h | 3 +++
arch/arm64/kvm/sys_regs.c | 37 ++++++++++++++++++++++++++-------
2 files changed, 33 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index abc85eaa453d..906a3550fc50 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -128,12 +128,15 @@
#define SYS_DBGWVRn_EL1(n) sys_reg(2, 0, 0, n, 6)
#define SYS_DBGWCRn_EL1(n) sys_reg(2, 0, 0, n, 7)
#define SYS_MDRAR_EL1 sys_reg(2, 0, 1, 0, 0)
+
#define SYS_OSLAR_EL1 sys_reg(2, 0, 1, 0, 4)
+#define SYS_OSLAR_OSLK BIT(0)
#define SYS_OSLSR_EL1 sys_reg(2, 0, 1, 1, 4)
#define SYS_OSLSR_OSLM_MASK (BIT(3) | BIT(0))
#define SYS_OSLSR_OSLM_NI 0
#define SYS_OSLSR_OSLM_IMPLEMENTED BIT(3)
+#define SYS_OSLSR_OSLK BIT(1)
#define SYS_OSDLR_EL1 sys_reg(2, 0, 1, 3, 4)
#define SYS_DBGPRCR_EL1 sys_reg(2, 0, 1, 4, 4)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index b8286c31e01c..b0d7240ef49f 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -44,6 +44,10 @@
* 64bit interface.
*/
+static int reg_from_user(u64 *val, const void __user *uaddr, u64 id);
+static int reg_to_user(void __user *uaddr, const u64 *val, u64 id);
+static u64 sys_reg_to_index(const struct sys_reg_desc *reg);
+
static bool read_from_write_only(struct kvm_vcpu *vcpu,
struct sys_reg_params *params,
const struct sys_reg_desc *r)
@@ -287,6 +291,24 @@ static bool trap_loregion(struct kvm_vcpu *vcpu,
return trap_raz_wi(vcpu, p, r);
}
+static bool trap_oslar_el1(struct kvm_vcpu *vcpu,
+ struct sys_reg_params *p,
+ const struct sys_reg_desc *r)
+{
+ u64 oslsr;
+
+ if (!p->is_write)
+ return read_from_write_only(vcpu, p, r);
+
+ /* Forward the OSLK bit to OSLSR */
+ oslsr = __vcpu_sys_reg(vcpu, OSLSR_EL1) & ~SYS_OSLSR_OSLK;
+ if (p->regval & SYS_OSLAR_OSLK)
+ oslsr |= SYS_OSLSR_OSLK;
+
+ __vcpu_sys_reg(vcpu, OSLSR_EL1) = oslsr;
+ return true;
+}
+
static bool trap_oslsr_el1(struct kvm_vcpu *vcpu,
struct sys_reg_params *p,
const struct sys_reg_desc *r)
@@ -309,9 +331,14 @@ static int set_oslsr_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
if (err)
return err;
- if (val != rd->val)
+ /*
+ * The only modifiable bit is the OSLK bit. Refuse the write if
+ * userspace attempts to change any other bit in the register.
+ */
+ if ((val ^ rd->val) & ~SYS_OSLSR_OSLK)
return -EINVAL;
+ __vcpu_sys_reg(vcpu, rd->reg) = val;
return 0;
}
@@ -1180,10 +1207,6 @@ static bool access_raz_id_reg(struct kvm_vcpu *vcpu,
return __access_id_reg(vcpu, p, r, true);
}
-static int reg_from_user(u64 *val, const void __user *uaddr, u64 id);
-static int reg_to_user(void __user *uaddr, const u64 *val, u64 id);
-static u64 sys_reg_to_index(const struct sys_reg_desc *reg);
-
/* Visibility overrides for SVE-specific control registers */
static unsigned int sve_visibility(const struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd)
@@ -1463,7 +1486,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
DBG_BCR_BVR_WCR_WVR_EL1(15),
{ SYS_DESC(SYS_MDRAR_EL1), trap_raz_wi },
- { SYS_DESC(SYS_OSLAR_EL1), trap_raz_wi },
+ { SYS_DESC(SYS_OSLAR_EL1), trap_oslar_el1 },
{ SYS_DESC(SYS_OSLSR_EL1), trap_oslsr_el1, reset_val, OSLSR_EL1,
SYS_OSLSR_OSLM_IMPLEMENTED, .set_user = set_oslsr_el1, },
{ SYS_DESC(SYS_OSDLR_EL1), trap_raz_wi },
@@ -1937,7 +1960,7 @@ static const struct sys_reg_desc cp14_regs[] = {
DBGBXVR(0),
/* DBGOSLAR */
- { Op1( 0), CRn( 1), CRm( 0), Op2( 4), trap_raz_wi },
+ { Op1( 0), CRn( 1), CRm( 0), Op2( 4), trap_oslar_el1 },
DBGBXVR(1),
/* DBGOSLSR */
{ Op1( 0), CRn( 1), CRm( 1), Op2( 4), trap_oslsr_el1, NULL, OSLSR_EL1 },
--
2.35.0.263.gb82422642f-goog
