From 182936eee7e6b1956881b51bc534a541dc71a101 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 9 Jun 2017 12:49:41 +0100 Subject: [PATCH] KVM: arm64: Enable GICv3 Group-1 sysreg trapping via command-line Now that we're able to safely handle Group-1 sysreg access, let's give the user the opportunity to enable it by passing a specific command-line option (vgic_v3.group1_trap). Tested-by: Alexander Graf Acked-by: David Daney Signed-off-by: Marc Zyngier Acked-by: Christoffer Dall Signed-off-by: Christoffer Dall --- Documentation/admin-guide/kernel-parameters.txt | 4 ++++ virt/kvm/arm/vgic/vgic-v3.c | 11 +++++++++++ 2 files changed, 15 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 15f79c27748d..42fe395be6c8 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1829,6 +1829,10 @@ for all guests. Default is 1 (enabled) if in 64-bit or 32-bit PAE mode. + kvm-arm.vgic_v3_group1_trap= + [KVM,ARM] Trap guest accesses to GICv3 group-1 + system registers + kvm-intel.ept= [KVM,Intel] Disable extended page tables (virtualized MMU) support on capable Intel chips. Default is 1 (enabled) diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c index 722bdebdfbb5..4b2b62b73470 100644 --- a/virt/kvm/arm/vgic/vgic-v3.c +++ b/virt/kvm/arm/vgic/vgic-v3.c @@ -435,6 +435,12 @@ out: DEFINE_STATIC_KEY_FALSE(vgic_v3_cpuif_trap); +static int __init early_group1_trap_cfg(char *buf) +{ + return strtobool(buf, &group1_trap); +} +early_param("kvm-arm.vgic_v3_group1_trap", early_group1_trap_cfg); + /** * vgic_v3_probe - probe for a GICv3 compatible interrupt controller in DT * @node: pointer to the DT node @@ -486,6 +492,11 @@ int vgic_v3_probe(const struct gic_kvm_info *info) if (kvm_vgic_global_state.vcpu_base == 0) kvm_info("disabling GICv2 emulation\n"); + if (group1_trap) { + kvm_info("GICv3 sysreg trapping enabled (reduced performance)\n"); + static_branch_enable(&vgic_v3_cpuif_trap); + } + kvm_vgic_global_state.vctrl_base = NULL; kvm_vgic_global_state.type = VGIC_V3; kvm_vgic_global_state.max_gic_vcpus = VGIC_V3_MAX_CPUS;