[PATCH v1 10/11] KVM: arm64: Add primitives to flush/sync the VGIC state at EL2

[tabba at google.com]

From: Marc Zyngier <maz at kernel.org>

pKVM performs its own world switch for protected VMs but has no
primitives to move the per-vCPU VGIC state between the host and
hypervisor vCPU contexts.

Add flush_hyp_vgic_state() and sync_hyp_vgic_state(). Flush copies
vgic_hcr, the in-use list registers and used_lrs from the host into the
hyp vCPU and pins vgic_sre to a fixed value; sync copies vgic_hcr,
vgic_vmcr and the in-use list registers back. The active priority
registers are handled separately by the save/restore-aprs path.

Signed-off-by: Marc Zyngier <maz at kernel.org>
Co-developed-by: Fuad Tabba <tabba at google.com>
Signed-off-by: Fuad Tabba <tabba at google.com>
---
 arch/arm64/kvm/hyp/nvhe/hyp-main.c | 50 +++++++++++++++++++++++++-----
 1 file changed, 42 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 2f165b6c7b07..23e644c24a03 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -99,6 +99,46 @@ static void fpsimd_sve_sync(struct kvm_vcpu *vcpu)
 	*host_data_ptr(fp_owner) = FP_STATE_HOST_OWNED;
 }
 
+static void flush_hyp_vgic_state(struct pkvm_hyp_vcpu *hyp_vcpu)
+{
+	struct kvm_vcpu *host_vcpu = hyp_vcpu->host_vcpu;
+	struct vgic_v3_cpu_if *host_cpu_if, *hyp_cpu_if;
+	unsigned int used_lrs, max_lrs, i;
+
+	host_cpu_if	= &host_vcpu->arch.vgic_cpu.vgic_v3;
+	hyp_cpu_if	= &hyp_vcpu->vcpu.arch.vgic_cpu.vgic_v3;
+
+	max_lrs		= (read_gicreg(ICH_VTR_EL2) & ICH_VTR_EL2_ListRegs) + 1;
+	used_lrs	= host_cpu_if->used_lrs;
+	used_lrs	= min(used_lrs, max_lrs);
+
+	hyp_cpu_if->vgic_hcr	= host_cpu_if->vgic_hcr;
+	/* Should be a one-off */
+	hyp_cpu_if->vgic_sre	= (ICC_SRE_EL1_DIB |
+				   ICC_SRE_EL1_DFB |
+				   ICC_SRE_EL1_SRE);
+	hyp_cpu_if->used_lrs	= used_lrs;
+
+	for (i = 0; i < used_lrs; i++)
+		hyp_cpu_if->vgic_lr[i] = host_cpu_if->vgic_lr[i];
+}
+
+static void sync_hyp_vgic_state(struct pkvm_hyp_vcpu *hyp_vcpu)
+{
+	struct kvm_vcpu *host_vcpu = hyp_vcpu->host_vcpu;
+	struct vgic_v3_cpu_if *host_cpu_if, *hyp_cpu_if;
+	unsigned int i;
+
+	host_cpu_if	= &host_vcpu->arch.vgic_cpu.vgic_v3;
+	hyp_cpu_if	= &hyp_vcpu->vcpu.arch.vgic_cpu.vgic_v3;
+
+	host_cpu_if->vgic_hcr = hyp_cpu_if->vgic_hcr;
+	host_cpu_if->vgic_vmcr = hyp_cpu_if->vgic_vmcr;
+
+	for (i = 0; i < hyp_cpu_if->used_lrs; i++)
+		host_cpu_if->vgic_lr[i] = hyp_cpu_if->vgic_lr[i];
+}
+
 static void flush_debug_state(struct pkvm_hyp_vcpu *hyp_vcpu)
 {
 	struct kvm_vcpu *host_vcpu = hyp_vcpu->host_vcpu;
@@ -139,7 +179,7 @@ static void flush_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu)
 
 	hyp_vcpu->vcpu.arch.vsesr_el2	= host_vcpu->arch.vsesr_el2;
 
-	hyp_vcpu->vcpu.arch.vgic_cpu.vgic_v3 = host_vcpu->arch.vgic_cpu.vgic_v3;
+	flush_hyp_vgic_state(hyp_vcpu);
 
 	hyp_vcpu->vcpu.arch.pid = host_vcpu->arch.pid;
 }
@@ -147,9 +187,6 @@ static void flush_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu)
 static void sync_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu)
 {
 	struct kvm_vcpu *host_vcpu = hyp_vcpu->host_vcpu;
-	struct vgic_v3_cpu_if *hyp_cpu_if = &hyp_vcpu->vcpu.arch.vgic_cpu.vgic_v3;
-	struct vgic_v3_cpu_if *host_cpu_if = &host_vcpu->arch.vgic_cpu.vgic_v3;
-	unsigned int i;
 
 	fpsimd_sve_sync(&hyp_vcpu->vcpu);
 	sync_debug_state(hyp_vcpu);
@@ -162,10 +199,7 @@ static void sync_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu)
 
 	host_vcpu->arch.iflags		= hyp_vcpu->vcpu.arch.iflags;
 
-	host_cpu_if->vgic_hcr		= hyp_cpu_if->vgic_hcr;
-	host_cpu_if->vgic_vmcr		= hyp_cpu_if->vgic_vmcr;
-	for (i = 0; i < hyp_cpu_if->used_lrs; ++i)
-		host_cpu_if->vgic_lr[i] = hyp_cpu_if->vgic_lr[i];
+	sync_hyp_vgic_state(hyp_vcpu);
 }
 
 static void handle___pkvm_vcpu_load(struct kvm_cpu_context *host_ctxt)
-- 
2.54.0.1136.gdb2ca164c4-goog