Commit 95537f06 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

KVM: arm64: nv: Add trap forwarding for ERET and SMC 



Honor the trap forwarding bits for both ERET and SMC, using a new
helper that checks for common conditions.

Reviewed-by: default avatarJoey Gouly <joey.gouly@arm.com>
Co-developed-by: default avatarJintack Lim <jintack.lim@linaro.org>
Signed-off-by: default avatarJintack Lim <jintack.lim@linaro.org>
Reviewed-by: default avatarOliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240419102935.1935571-7-maz@kernel.org


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 04ab519b

arch/arm64/include/asm/kvm_nested.h

+1 −0
Original line number Diff line number Diff line
@@ -60,6 +60,7 @@ static inline u64 translate_ttbr0_el2_to_ttbr0_el1(u64 ttbr0) 
	return ttbr0 & ~GENMASK_ULL(63, 48);

}



extern bool forward_smc_trap(struct kvm_vcpu *vcpu);



int kvm_init_nv_sysregs(struct kvm *kvm);

arch/arm64/kvm/emulate-nested.c

+27 −0
Original line number Diff line number Diff line
@@ -2117,6 +2117,26 @@ bool triage_sysreg_trap(struct kvm_vcpu *vcpu, int *sr_index) 
	return true;

}



static bool forward_traps(struct kvm_vcpu *vcpu, u64 control_bit)

{

	bool control_bit_set;



	if (!vcpu_has_nv(vcpu))

		return false;



	control_bit_set = __vcpu_sys_reg(vcpu, HCR_EL2) & control_bit;

	if (!is_hyp_ctxt(vcpu) && control_bit_set) {

		kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu));

		return true;

	}

	return false;

}



bool forward_smc_trap(struct kvm_vcpu *vcpu)

{

	return forward_traps(vcpu, HCR_TSC);

}



static u64 kvm_check_illegal_exception_return(struct kvm_vcpu *vcpu, u64 spsr)

{

	u64 mode = spsr & PSR_MODE_MASK;
@@ -2155,6 +2175,13 @@ void kvm_emulate_nested_eret(struct kvm_vcpu *vcpu) 
	u64 spsr, elr, mode;

	bool direct_eret;



	/*

	 * Forward this trap to the virtual EL2 if the virtual

	 * HCR_EL2.NV bit is set and this is coming from !EL2.

	 */

	if (forward_traps(vcpu, HCR_NV))

		return;



	/*

	 * Going through the whole put/load motions is a waste of time

	 * if this is a VHE guest hypervisor returning to its own

arch/arm64/kvm/handle_exit.c

+7 −0
Original line number Diff line number Diff line
@@ -55,6 +55,13 @@ static int handle_hvc(struct kvm_vcpu *vcpu) 


static int handle_smc(struct kvm_vcpu *vcpu)

{

	/*

	 * Forward this trapped smc instruction to the virtual EL2 if

	 * the guest has asked for it.

	 */

	if (forward_smc_trap(vcpu))

		return 1;



	/*

	 * "If an SMC instruction executed at Non-secure EL1 is

	 * trapped to EL2 because HCR_EL2.TSC is 1, the exception is a