Commit 3e6245eb authored by Marc Zyngier's avatar Marc Zyngier Committed by Oliver Upton
Browse files

KVM: arm64: Make ICC_*SGI*_EL1 undef in the absence of a vGICv3 



On a system with a GICv3, if a guest hasn't been configured with
GICv3 and that the host is not capable of GICv2 emulation,
a write to any of the ICC_*SGI*_EL1 registers is trapped to EL2.

We therefore try to emulate the SGI access, only to hit a NULL
pointer as no private interrupt is allocated (no GIC, remember?).

The obvious fix is to give the guest what it deserves, in the
shape of a UNDEF exception.

Reported-by: default avatarAlexander Potapenko <glider@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240820100349.3544850-2-maz@kernel.org


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent 1d8c3c23

arch/arm64/kvm/sys_regs.c

+6 −0
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ 
#include <trace/events/kvm.h>



#include "sys_regs.h"

#include "vgic/vgic.h"



#include "trace.h"
@@ -435,6 +436,11 @@ static bool access_gic_sgi(struct kvm_vcpu *vcpu, 
{

	bool g1;



	if (!kvm_has_gicv3(vcpu->kvm)) {

		kvm_inject_undefined(vcpu);

		return false;

	}



	if (!p->is_write)

		return read_from_write_only(vcpu, p, r);

arch/arm64/kvm/vgic/vgic.h

+7 −0
Original line number Diff line number Diff line
@@ -346,4 +346,11 @@ void vgic_v4_configure_vsgis(struct kvm *kvm); 
void vgic_v4_get_vlpi_state(struct vgic_irq *irq, bool *val);

int vgic_v4_request_vpe_irq(struct kvm_vcpu *vcpu, int irq);



static inline bool kvm_has_gicv3(struct kvm *kvm)

{

	return (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif) &&

		irqchip_in_kernel(kvm) &&

		kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3);

}



#endif