Commit 493da2b1 authored by Marc Zyngier's avatar Marc Zyngier Committed by Oliver Upton
Browse files

KVM: arm64: nv: Handle CPACR_EL1 traps 



Handle CPACR_EL1 accesses when running a VHE guest. In order to
limit the cost of the emulation, implement it ass a shallow exit.

In the other cases:

- this is a nVHE L1 which will write to memory, and we don't trap

- this is a L2 guest:

  * the L1 has CPTR_EL2.TCPAC==0, and the L2 has direct register
   access

  * the L1 has CPTR_EL2.TCPAC==1, and the L2 will trap, but the
    handling is defered to the general handling for forwarding

Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240620164653.1130714-10-oliver.upton@linux.dev


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent 1785f020

arch/arm64/kvm/hyp/vhe/switch.c

+31 −1
Original line number Diff line number Diff line
@@ -266,10 +266,40 @@ static void kvm_hyp_save_fpsimd_host(struct kvm_vcpu *vcpu) 
	__fpsimd_save_state(*host_data_ptr(fpsimd_state));

}



static bool kvm_hyp_handle_cpacr_el1(struct kvm_vcpu *vcpu, u64 *exit_code)

{

	u64 esr = kvm_vcpu_get_esr(vcpu);

	int rt;



	if (!is_hyp_ctxt(vcpu) || esr_sys64_to_sysreg(esr) != SYS_CPACR_EL1)

		return false;



	rt = kvm_vcpu_sys_get_rt(vcpu);



	if ((esr & ESR_ELx_SYS64_ISS_DIR_MASK) == ESR_ELx_SYS64_ISS_DIR_READ) {

		vcpu_set_reg(vcpu, rt, __vcpu_sys_reg(vcpu, CPTR_EL2));

	} else {

		vcpu_write_sys_reg(vcpu, vcpu_get_reg(vcpu, rt), CPTR_EL2);

		__activate_cptr_traps(vcpu);

	}



	__kvm_skip_instr(vcpu);



	return true;

}



static bool kvm_hyp_handle_sysreg_vhe(struct kvm_vcpu *vcpu, u64 *exit_code)

{

	if (kvm_hyp_handle_cpacr_el1(vcpu, exit_code))

		return true;



	return kvm_hyp_handle_sysreg(vcpu, exit_code);

}



static const exit_handler_fn hyp_exit_handlers[] = {

	[0 ... ESR_ELx_EC_MAX]		= NULL,

	[ESR_ELx_EC_CP15_32]		= kvm_hyp_handle_cp15_32,

	[ESR_ELx_EC_SYS64]		= kvm_hyp_handle_sysreg,

	[ESR_ELx_EC_SYS64]		= kvm_hyp_handle_sysreg_vhe,

	[ESR_ELx_EC_SVE]		= kvm_hyp_handle_fpsimd,

	[ESR_ELx_EC_FP_ASIMD]		= kvm_hyp_handle_fpsimd,

	[ESR_ELx_EC_IABT_LOW]		= kvm_hyp_handle_iabt_low,