[RFC 17/55] KVM: arm64: Trap SPSR_EL1, ELR_EL1 and VBAR_EL1 in virtual EL2

Jintack Lim
2017-01-09T06:24:13Z

For the same reason we trap virtual memory register accesses in virtual
EL2, we need to trap SPSR_EL1, ELR_EL1 and VBAR_EL1 accesses. ARM v8.3
introduces the HCR_EL2.NV1 bit to be able to trap on those register
accesses in EL1. Do not set this bit until the whole nesting support is
complete.

Signed-off-by: Jintack Lim <jintack@cs.columbia.edu>
---
arch/arm64/kvm/sys_regs.c | 41 ++++++++++++++++++++++++++++++++++++++++-
1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 0f5d21b..19d6a6e 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -898,6 +898,38 @@ static bool access_cntp_cval(struct kvm_vcpu *vcpu,
return true;
}

+static inline void access_rw(struct sys_reg_params *p, u64 *sysreg)
+{
+ if (!p->is_write)
+ p->regval = *sysreg;
+ else
+ *sysreg = p->regval;
+}
+
+static bool access_elr(struct kvm_vcpu *vcpu,
+ struct sys_reg_params *p,
+ const struct sys_reg_desc *r)
+{
+ access_rw(p, &vcpu->arch.ctxt.gp_regs.elr_el1);
+ return true;
+}
+
+static bool access_spsr(struct kvm_vcpu *vcpu,
+ struct sys_reg_params *p,
+ const struct sys_reg_desc *r)
+{
+ access_rw(p, &vcpu->arch.ctxt.gp_regs.spsr[KVM_SPSR_EL1]);
+ return true;
+}
+
+static bool access_vbar(struct kvm_vcpu *vcpu,
+ struct sys_reg_params *p,
+ const struct sys_reg_desc *r)
+{
+ access_rw(p, &vcpu_sys_reg(vcpu, r->reg));
+ return true;
+}
+
static bool trap_el2_reg(struct kvm_vcpu *vcpu,
struct sys_reg_params *p,
const struct sys_reg_desc *r)
@@ -1013,6 +1045,13 @@ static bool trap_el2_reg(struct kvm_vcpu *vcpu,
{ Op0(0b11), Op1(0b000), CRn(0b0010), CRm(0b0000), Op2(0b010),
access_vm_reg, reset_val, TCR_EL1, 0 },

+ /* SPSR_EL1 */
+ { Op0(0b11), Op1(0b000), CRn(0b0100), CRm(0b0000), Op2(0b000),
+ access_spsr},
+ /* ELR_EL1 */
+ { Op0(0b11), Op1(0b000), CRn(0b0100), CRm(0b0000), Op2(0b001),
+ access_elr},
+
/* AFSR0_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b0101), CRm(0b0001), Op2(0b000),
access_vm_reg, reset_unknown, AFSR0_EL1 },
@@ -1045,7 +1084,7 @@ static bool trap_el2_reg(struct kvm_vcpu *vcpu,

/* VBAR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b1100), CRm(0b0000), Op2(0b000),
- NULL, reset_val, VBAR_EL1, 0 },
+ access_vbar, reset_val, VBAR_EL1, 0 },

/* ICC_SGI1R_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b1100), CRm(0b1011), Op2(0b101),
--
1.9.1