[PATCH v6 62/64] KVM: arm64: nv: Enable ARMv8.4-NV support

Marc Zyngier
2022-01-28T13:00:59Z

As all the VNCR-capable system registers are nicely separated
from the rest of the crowd, let's set HCR_EL2.NV2 on and let
the ball rolling.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/include/asm/kvm_arm.h | 1 +
arch/arm64/include/asm/kvm_emulate.h | 23 +++++++++++++----------
arch/arm64/include/asm/sysreg.h | 1 +
arch/arm64/kvm/hyp/vhe/switch.c | 14 +++++++++++++-
4 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index aa3bdce1b166..19998cf067ce 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -20,6 +20,7 @@
#define HCR_AMVOFFEN (UL(1) << 51)
#define HCR_FIEN (UL(1) << 47)
#define HCR_FWB (UL(1) << 46)
+#define HCR_NV2 (UL(1) << 45)
#define HCR_AT (UL(1) << 44)
#define HCR_NV1 (UL(1) << 43)
#define HCR_NV (UL(1) << 42)
diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 2128d623a8b3..7c09d36fd593 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -245,21 +245,24 @@ static inline bool is_hyp_ctxt(const struct kvm_vcpu *vcpu)

static inline u64 __fixup_spsr_el2_write(struct kvm_cpu_context *ctxt, u64 val)
{
- if (!__vcpu_el2_e2h_is_set(ctxt)) {
- /*
- * Clear the .M field when writing SPSR to the CPU, so that we
- * can detect when the CPU clobbered our SPSR copy during a
- * local exception.
- */
- val &= ~0xc;
- }
+ struct kvm_vcpu *vcpu = container_of(ctxt, struct kvm_vcpu, arch.ctxt);
+
+ if (vcpu_has_nv2(vcpu) || __vcpu_el2_e2h_is_set(ctxt))
+ return val;

- return val;
+ /*
+ * Clear the .M field when writing SPSR to the CPU, so that we
+ * can detect when the CPU clobbered our SPSR copy during a
+ * local exception.
+ */
+ return val &= ~0xc;
}

static inline u64 __fixup_spsr_el2_read(const struct kvm_cpu_context *ctxt, u64 val)
{
- if (__vcpu_el2_e2h_is_set(ctxt))
+ struct kvm_vcpu *vcpu = container_of(ctxt, struct kvm_vcpu, arch.ctxt);
+
+ if (vcpu_has_nv2(vcpu) || __vcpu_el2_e2h_is_set(ctxt))
return val;

/*
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index ff6d3af8ed34..0a21be5263d9 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -551,6 +551,7 @@
#define SYS_TCR_EL2 sys_reg(3, 4, 2, 0, 2)
#define SYS_VTTBR_EL2 sys_reg(3, 4, 2, 1, 0)
#define SYS_VTCR_EL2 sys_reg(3, 4, 2, 1, 2)
+#define SYS_VNCR_EL2 sys_reg(3, 4, 2, 2, 0)

#define SYS_ZCR_EL2 sys_reg(3, 4, 1, 2, 0)
#define SYS_TRFCR_EL2 sys_reg(3, 4, 1, 2, 1)
diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
index 5e8eafac27c6..65120c9027d6 100644
--- a/arch/arm64/kvm/hyp/vhe/switch.c
+++ b/arch/arm64/kvm/hyp/vhe/switch.c
@@ -44,7 +44,13 @@ static void __activate_traps(struct kvm_vcpu *vcpu)
* the EL1 virtual memory control register accesses
* as well as the AT S1 operations.
*/
- hcr |= HCR_TVM | HCR_TRVM | HCR_AT | HCR_TTLB | HCR_NV1;
+ if (vcpu_has_nv2(vcpu)) {
+ hcr &= ~HCR_TVM;
+ } else {
+ hcr |= HCR_TVM | HCR_TRVM | HCR_TTLB;
+ }
+
+ hcr |= HCR_AT | HCR_NV1;
} else {
/*
* For a guest hypervisor on v8.1 (VHE), allow to
@@ -78,6 +84,12 @@ static void __activate_traps(struct kvm_vcpu *vcpu)
if (!vcpu_el2_tge_is_set(vcpu))
hcr |= HCR_AT | HCR_TTLB;
}
+
+ if (vcpu_has_nv2(vcpu)) {
+ hcr |= HCR_AT | HCR_TTLB | HCR_NV2;
+ write_sysreg_s(vcpu->arch.ctxt.vncr_array,
+ SYS_VNCR_EL2);
+ }
} else if (vcpu_has_nv(vcpu)) {
u64 vhcr_el2 = __vcpu_sys_reg(vcpu, HCR_EL2);