[PATCH v3 26/66] KVM: arm64: nv: Respect the virtual HCR_EL2.NV1 bit setting

Marc Zyngier
2020-12-10T16:30:22Z

From: Jintack Lim <jintack@cs.columbia.edu>

Forward ELR_EL1, SPSR_EL1 and VBAR_EL1 traps to the virtual EL2 if the
virtual HCR_EL2.NV bit is set.

This is for recursive nested virtualization.

Signed-off-by: Jintack Lim <jintack@cs.columbia.edu>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/include/asm/kvm_arm.h | 1 +
arch/arm64/kvm/sys_regs.c | 28 +++++++++++++++++++++++++++-
2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index c18edb1b35bf..3d2abc40d3a2 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -14,6 +14,7 @@
/* Hyp Configuration Register (HCR) bits */
#define HCR_ATA (UL(1) << 56)
#define HCR_FWB (UL(1) << 46)
+#define HCR_NV1 (UL(1) << 43)
#define HCR_NV (UL(1) << 42)
#define HCR_API (UL(1) << 41)
#define HCR_APK (UL(1) << 40)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index d09fda0fd76f..ea511e569ee0 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -299,6 +299,22 @@ static bool access_wi(struct kvm_vcpu *vcpu,
return true;
}

+/* This function is to support the recursive nested virtualization */
+static bool forward_nv1_traps(struct kvm_vcpu *vcpu, struct sys_reg_params *p)
+{
+ return forward_traps(vcpu, HCR_NV1);
+}
+
+static bool access_vbar_el1(struct kvm_vcpu *vcpu,
+ struct sys_reg_params *p,
+ const struct sys_reg_desc *r)
+{
+ if (forward_nv1_traps(vcpu, p))
+ return false;
+
+ return access_rw(vcpu, p, r);
+}
+
static bool access_sctlr_el2(struct kvm_vcpu *vcpu,
struct sys_reg_params *p,
const struct sys_reg_desc *r)
@@ -1589,6 +1605,7 @@ static bool access_sp_el1(struct kvm_vcpu *vcpu,
return true;
}

+
static bool access_elr(struct kvm_vcpu *vcpu,
struct sys_reg_params *p,
const struct sys_reg_desc *r)
@@ -1596,6 +1613,9 @@ static bool access_elr(struct kvm_vcpu *vcpu,
if (el12_reg(p) && forward_nv_traps(vcpu))
return false;

+ if (!el12_reg(p) && forward_nv1_traps(vcpu, p))
+ return false;
+
if (p->is_write)
vcpu_write_sys_reg(vcpu, p->regval, ELR_EL1);
else
@@ -1611,6 +1631,9 @@ static bool access_spsr(struct kvm_vcpu *vcpu,
if (el12_reg(p) && forward_nv_traps(vcpu))
return false;

+ if (!el12_reg(p) && forward_nv1_traps(vcpu, p))
+ return false;
+
if (p->is_write)
__vcpu_sys_reg(vcpu, SPSR_EL1) = p->regval;
else
@@ -1626,6 +1649,9 @@ static bool access_spsr_el2(struct kvm_vcpu *vcpu,
if (el12_reg(p) && forward_nv_traps(vcpu))
return false;

+ if (!el12_reg(p) && forward_nv1_traps(vcpu, p))
+ return false;
+
if (p->is_write)
vcpu_write_sys_reg(vcpu, p->regval, SPSR_EL2);
else
@@ -1817,7 +1843,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
{ SYS_DESC(SYS_LORC_EL1), trap_loregion },
{ SYS_DESC(SYS_LORID_EL1), trap_loregion },

- { SYS_DESC(SYS_VBAR_EL1), access_rw, reset_val, VBAR_EL1, 0 },
+ { SYS_DESC(SYS_VBAR_EL1), access_vbar_el1, reset_val, VBAR_EL1, 0 },
{ SYS_DESC(SYS_DISR_EL1), NULL, reset_val, DISR_EL1, 0 },

{ SYS_DESC(SYS_ICC_IAR0_EL1), write_to_read_only },
--
2.29.2