[PATCH v5 25/49] KVM: arm64: gic-v5: Add GIC VDPEND hyp call

[Sascha Bischoff]

With PPIs, their state is injected via the ICH_PPI_x_EL2 system
registers. For SPIs and LPIs, there are no such registers as these
would limit the number of interrupts significantly. Instead, SPI and
LPI pending state can be managed from the hypervisor using the GIC
VDPEND instruction. This provides a way to set an SPI or LPI for a VM
as pending or non-pending, i.e., to inject interrupts into a guest.

This system instruction is only executable from EL2, and therefore
must be wrapped in a hypercall for NVHE/hVHE configurations.

With pKVM this hypercall is explicitly a no-op as we currently don't
support the combination of GICv5 and pKVM.

Signed-off-by: Sascha Bischoff <sascha.bischoff at arm.com>
---
 arch/arm64/include/asm/kvm_asm.h   |  1 +
 arch/arm64/include/asm/kvm_hyp.h   |  1 +
 arch/arm64/kvm/hyp/nvhe/hyp-main.c | 13 +++++++++++++
 arch/arm64/kvm/hyp/vgic-v5-sr.c    | 10 ++++++++++
 4 files changed, 25 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index d9ff9c2999aa7..36808ed0e9afe 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -89,6 +89,7 @@ enum __kvm_host_smccc_func {
 	__KVM_HOST_SMCCC_FUNC___vgic_v3_restore_vmcr_aprs,
 	__KVM_HOST_SMCCC_FUNC___vgic_v5_make_resident,
 	__KVM_HOST_SMCCC_FUNC___vgic_v5_make_non_resident,
+	__KVM_HOST_SMCCC_FUNC___vgic_v5_vdpend,
 	__KVM_HOST_SMCCC_FUNC___vgic_v5_save_apr,
 	__KVM_HOST_SMCCC_FUNC___vgic_v5_restore_vmcr_apr,
 
diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
index 8fcbbff719cce..8e2f0280c0cc5 100644
--- a/arch/arm64/include/asm/kvm_hyp.h
+++ b/arch/arm64/include/asm/kvm_hyp.h
@@ -97,6 +97,7 @@ void __vgic_v5_save_ppi_state(struct vgic_v5_cpu_if *cpu_if);
 void __vgic_v5_restore_ppi_state(struct vgic_v5_cpu_if *cpu_if);
 void __vgic_v5_save_state(struct vgic_v5_cpu_if *cpu_if);
 void __vgic_v5_restore_state(struct vgic_v5_cpu_if *cpu_if);
+void __vgic_v5_vdpend(u32 intid, bool pending, u16 vm);
 
 #ifdef __KVM_NVHE_HYPERVISOR__
 void __timer_enable_traps(struct kvm_vcpu *vcpu);
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 7fdcc6bb6f594..a372702aaf5a8 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -725,6 +725,18 @@ static void handle___vgic_v5_restore_vmcr_apr(struct kvm_cpu_context *host_ctxt)
 	__vgic_v5_restore_vmcr_apr(kern_hyp_va(cpu_if));
 }
 
+static void handle___vgic_v5_vdpend(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(u32, intid, host_ctxt, 1);
+	DECLARE_REG(bool, pending, host_ctxt, 2);
+	DECLARE_REG(u16, vm, host_ctxt, 3);
+
+	if (unlikely(is_protected_kvm_enabled()))
+		return;
+
+	__vgic_v5_vdpend(intid, pending, vm);
+}
+
 typedef void (*hcall_t)(struct kvm_cpu_context *);
 
 #define HANDLE_FUNC(x)	[__KVM_HOST_SMCCC_FUNC_##x] = (hcall_t)handle_##x
@@ -760,6 +772,7 @@ static const hcall_t host_hcall[] = {
 	HANDLE_FUNC(__vgic_v3_restore_vmcr_aprs),
 	HANDLE_FUNC(__vgic_v5_make_resident),
 	HANDLE_FUNC(__vgic_v5_make_non_resident),
+	HANDLE_FUNC(__vgic_v5_vdpend),
 	HANDLE_FUNC(__vgic_v5_save_apr),
 	HANDLE_FUNC(__vgic_v5_restore_vmcr_apr),
 
diff --git a/arch/arm64/kvm/hyp/vgic-v5-sr.c b/arch/arm64/kvm/hyp/vgic-v5-sr.c
index 46992a6c2cacb..94746317ca79f 100644
--- a/arch/arm64/kvm/hyp/vgic-v5-sr.c
+++ b/arch/arm64/kvm/hyp/vgic-v5-sr.c
@@ -149,3 +149,13 @@ void __vgic_v5_restore_state(struct vgic_v5_cpu_if *cpu_if)
 {
 	write_sysreg_s(cpu_if->vgic_icsr, SYS_ICC_ICSR_EL1);
 }
+
+void __vgic_v5_vdpend(u32 intid, bool pending, u16 vm)
+{
+	u64 value;
+
+	value = intid & (GICV5_GIC_VDPEND_ID_MASK | GICV5_GIC_VDPEND_TYPE_MASK);
+	value |= FIELD_PREP(GICV5_GIC_VDPEND_PENDING_MASK, pending);
+	value |= FIELD_PREP(GICV5_GIC_VDPEND_VM_MASK, vm);
+	gic_insn(value, VDPEND);
+}
-- 
2.34.1