vgic-v2-cpuif-proxy.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012-2015 - ARM Ltd
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 */
 
#include <hyp/adjust_pc.h>
 
#include <linux/compiler.h>
#include <linux/irqchip/arm-gic.h>
#include <linux/kvm_host.h>
#include <linux/swab.h>
 
#include <asm/kvm_emulate.h>
#include <asm/kvm_hyp.h>
#include <asm/kvm_mmu.h>
 
static bool __is_be(struct kvm_vcpu *vcpu)
{
    if (vcpu_mode_is_32bit(vcpu))
        return !!(read_sysreg_el2(SYS_SPSR) & PSR_AA32_E_BIT);
 
    return !!(read_sysreg(SCTLR_EL1) & SCTLR_ELx_EE);
}
 
/*
 * __vgic_v2_perform_cpuif_access -- perform a GICV access on behalf of the
 *                   guest.
 *
 * @vcpu: the offending vcpu
 *
 * Returns:
 *  1: GICV access successfully performed
 *  0: Not a GICV access
 * -1: Illegal GICV access successfully performed
 */
int __vgic_v2_perform_cpuif_access(struct kvm_vcpu *vcpu)
{
    struct kvm *kvm = kern_hyp_va(vcpu->kvm);
    struct vgic_dist *vgic = &kvm->arch.vgic;
    phys_addr_t fault_ipa;
    void __iomem *addr;
    int rd;
 
    /* Build the full address */
    fault_ipa  = kvm_vcpu_get_fault_ipa(vcpu);
    fault_ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
 
    /* If not for GICV, move on */
    if (fault_ipa <  vgic->vgic_cpu_base ||
        fault_ipa >= (vgic->vgic_cpu_base + KVM_VGIC_V2_CPU_SIZE))
        return 0;
 
    /* Reject anything but a 32bit access */
    if (kvm_vcpu_dabt_get_as(vcpu) != sizeof(u32)) {
        __kvm_skip_instr(vcpu);
        return -1;
    }
 
    /* Not aligned? Don't bother */
    if (fault_ipa & 3) {
        __kvm_skip_instr(vcpu);
        return -1;
    }
 
    rd = kvm_vcpu_dabt_get_rd(vcpu);
    addr  = kvm_vgic_global_state.vcpu_hyp_va;
    addr += fault_ipa - vgic->vgic_cpu_base;
 
    if (kvm_vcpu_dabt_iswrite(vcpu)) {
        u32 data = vcpu_get_reg(vcpu, rd);
        if (__is_be(vcpu)) {
            /* guest pre-swabbed data, undo this for writel() */
            data = __kvm_swab32(data);
        }
        writel_relaxed(data, addr);
    } else {
        u32 data = readl_relaxed(addr);
        if (__is_be(vcpu)) {
            /* guest expects swabbed data */
            data = __kvm_swab32(data);
        }
        vcpu_set_reg(vcpu, rd, data);
    }
 
    __kvm_skip_instr(vcpu);
 
    return 1;
}