Commit 0f1a6c5c authored by Oliver Upton's avatar Oliver Upton Committed by Marc Zyngier
Browse files

KVM: arm64: Flush/sync debug state in protected mode 



The recent changes to debug state management broke self-hosted debug for
guests when running in protected mode, since both the debug owner and
the debug state itself aren't shared with the hyp's view of the vcpu.

Fix it by flushing/syncing the relevant bits with the hyp vcpu.

Fixes: beb470d9 ("KVM: arm64: Use debug_owner to track if debug regs need save/restore")
Reported-by: default avatarMark Brown <broonie@kernel.org>
Closes: https://lore.kernel.org/kvmarm/5f62740f-a065-42d9-9f56-8fb648b9c63f@sirena.org.uk/


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20250131222922.1548780-3-oliver.upton@linux.dev


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 9bcbb610

arch/arm64/kvm/hyp/nvhe/hyp-main.c

+24 −0
Original line number Diff line number Diff line
@@ -91,11 +91,34 @@ static void fpsimd_sve_sync(struct kvm_vcpu *vcpu) 
	*host_data_ptr(fp_owner) = FP_STATE_HOST_OWNED;

}



static void flush_debug_state(struct pkvm_hyp_vcpu *hyp_vcpu)

{

	struct kvm_vcpu *host_vcpu = hyp_vcpu->host_vcpu;



	hyp_vcpu->vcpu.arch.debug_owner = host_vcpu->arch.debug_owner;



	if (kvm_guest_owns_debug_regs(&hyp_vcpu->vcpu))

		hyp_vcpu->vcpu.arch.vcpu_debug_state = host_vcpu->arch.vcpu_debug_state;

	else if (kvm_host_owns_debug_regs(&hyp_vcpu->vcpu))

		hyp_vcpu->vcpu.arch.external_debug_state = host_vcpu->arch.external_debug_state;

}



static void sync_debug_state(struct pkvm_hyp_vcpu *hyp_vcpu)

{

	struct kvm_vcpu *host_vcpu = hyp_vcpu->host_vcpu;



	if (kvm_guest_owns_debug_regs(&hyp_vcpu->vcpu))

		host_vcpu->arch.vcpu_debug_state = hyp_vcpu->vcpu.arch.vcpu_debug_state;

	else if (kvm_host_owns_debug_regs(&hyp_vcpu->vcpu))

		host_vcpu->arch.external_debug_state = hyp_vcpu->vcpu.arch.external_debug_state;

}



static void flush_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu)

{

	struct kvm_vcpu *host_vcpu = hyp_vcpu->host_vcpu;



	fpsimd_sve_flush();

	flush_debug_state(hyp_vcpu);



	hyp_vcpu->vcpu.arch.ctxt	= host_vcpu->arch.ctxt;
@@ -123,6 +146,7 @@ static void sync_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu) 
	unsigned int i;



	fpsimd_sve_sync(&hyp_vcpu->vcpu);

	sync_debug_state(hyp_vcpu);



	host_vcpu->arch.ctxt		= hyp_vcpu->vcpu.arch.ctxt;