From 42fe26543e66c27932b4c7f4c5c149e38f4e14b9 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 29 Jul 2026 14:18:22 +0100 Subject: [PATCH] KVM: arm64: Add primitives to flush/sync the VGIC state at EL2 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. Bound used_lrs by hyp_gicv3_nr_lr, the cached implemented-LR count, instead of reading ICH_VTR_EL2 on each entry. That clamps the host-supplied value and avoids a per-entry sysreg read that is costly under NV. Reviewed-by: Vincent Donnefort Signed-off-by: Marc Zyngier Co-developed-by: Fuad Tabba Signed-off-by: Fuad Tabba Link: https://patch.msgid.link/20260729131823.2021516-8-fuad.tabba@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/hyp/nvhe/hyp-main.c | 55 ++++++++++++++++++++++-------- 1 file changed, 41 insertions(+), 14 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index 415bbd7f9452..ac36257c8da2 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -104,6 +104,45 @@ 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, i; + + host_cpu_if = &host_vcpu->arch.vgic_cpu.vgic_v3; + hyp_cpu_if = &hyp_vcpu->vcpu.arch.vgic_cpu.vgic_v3; + + used_lrs = host_cpu_if->used_lrs; + used_lrs = min(used_lrs, hyp_gicv3_nr_lr); + + 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; @@ -158,13 +197,7 @@ 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; - - /* Bound used_lrs by the number of implemented list registers. */ - hyp_vcpu->vcpu.arch.vgic_cpu.vgic_v3.used_lrs = - min_t(unsigned int, - hyp_vcpu->vcpu.arch.vgic_cpu.vgic_v3.used_lrs, - hyp_gicv3_nr_lr); + flush_hyp_vgic_state(hyp_vcpu); hyp_vcpu->vcpu.arch.pid = host_vcpu->arch.pid; } @@ -172,9 +205,6 @@ 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); @@ -187,10 +217,7 @@ 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)