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KVM: arm64: Enable GICv3 Group-1 sysreg trapping via command-line

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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 <agraf@suse.de>
Acked-by: David Daney <david.daney@cavium.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
This commit is contained in:
Marc Zyngier 2017-06-09 12:49:41 +01:00
parent 9c7bfc288c
commit 182936eee7
2 changed files with 15 additions and 0 deletions
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4
Documentation/admin-guide/kernel-parameters.txt
View File

@ -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)

11
virt/kvm/arm/vgic/vgic-v3.c
View File

@ -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;