From 493da2b1c49ac86c0eb0dde9e42b79333272d1f9 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 20 Jun 2024 16:46:46 +0000 Subject: [PATCH] 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: Marc Zyngier Link: https://lore.kernel.org/r/20240620164653.1130714-10-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/hyp/vhe/switch.c | 32 +++++++++++++++++++++++++++++++- 1 file changed, 31 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c index 667ed4f558af..3d51789e7d77 100644 --- a/arch/arm64/kvm/hyp/vhe/switch.c +++ b/arch/arm64/kvm/hyp/vhe/switch.c @@ -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, -- 2.25.1