debug-sr.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2015 - ARM Ltd
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 */
 
#include <hyp/debug-sr.h>
 
#include <linux/compiler.h>
#include <linux/kvm_host.h>
 
#include <asm/debug-monitors.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_hyp.h>
#include <asm/kvm_mmu.h>
 
static void __debug_save_spe(u64 *pmscr_el1)
{
    u64 reg;
 
    /* Clear pmscr in case of early return */
    *pmscr_el1 = 0;
 
    /*
     * At this point, we know that this CPU implements
     * SPE and is available to the host.
     * Check if the host is actually using it ?
     */
    reg = read_sysreg_s(SYS_PMBLIMITR_EL1);
    if (!(reg & BIT(PMBLIMITR_EL1_E_SHIFT)))
        return;
 
    /* Yes; save the control register and disable data generation */
    *pmscr_el1 = read_sysreg_s(SYS_PMSCR_EL1);
    write_sysreg_s(0, SYS_PMSCR_EL1);
    isb();
 
    /* Now drain all buffered data to memory */
    psb_csync();
}
 
static void __debug_restore_spe(u64 pmscr_el1)
{
    if (!pmscr_el1)
        return;
 
    /* The host page table is installed, but not yet synchronised */
    isb();
 
    /* Re-enable data generation */
    write_sysreg_s(pmscr_el1, SYS_PMSCR_EL1);
}
 
static void __debug_save_trace(u64 *trfcr_el1)
{
    *trfcr_el1 = 0;
 
    /* Check if the TRBE is enabled */
    if (!(read_sysreg_s(SYS_TRBLIMITR_EL1) & TRBLIMITR_EL1_E))
        return;
    /*
     * Prohibit trace generation while we are in guest.
     * Since access to TRFCR_EL1 is trapped, the guest can't
     * modify the filtering set by the host.
     */
    *trfcr_el1 = read_sysreg_s(SYS_TRFCR_EL1);
    write_sysreg_s(0, SYS_TRFCR_EL1);
    isb();
    /* Drain the trace buffer to memory */
    tsb_csync();
}
 
static void __debug_restore_trace(u64 trfcr_el1)
{
    if (!trfcr_el1)
        return;
 
    /* Restore trace filter controls */
    write_sysreg_s(trfcr_el1, SYS_TRFCR_EL1);
}
 
void __debug_save_host_buffers_nvhe(struct kvm_vcpu *vcpu)
{
    /* Disable and flush SPE data generation */
    if (vcpu_get_flag(vcpu, DEBUG_STATE_SAVE_SPE))
        __debug_save_spe(&vcpu->arch.host_debug_state.pmscr_el1);
    /* Disable and flush Self-Hosted Trace generation */
    if (vcpu_get_flag(vcpu, DEBUG_STATE_SAVE_TRBE))
        __debug_save_trace(&vcpu->arch.host_debug_state.trfcr_el1);
}
 
void __debug_switch_to_guest(struct kvm_vcpu *vcpu)
{
    __debug_switch_to_guest_common(vcpu);
}
 
void __debug_restore_host_buffers_nvhe(struct kvm_vcpu *vcpu)
{
    if (vcpu_get_flag(vcpu, DEBUG_STATE_SAVE_SPE))
        __debug_restore_spe(vcpu->arch.host_debug_state.pmscr_el1);
    if (vcpu_get_flag(vcpu, DEBUG_STATE_SAVE_TRBE))
        __debug_restore_trace(vcpu->arch.host_debug_state.trfcr_el1);
}
 
void __debug_switch_to_host(struct kvm_vcpu *vcpu)
{
    __debug_switch_to_host_common(vcpu);
}
 
u64 __kvm_get_mdcr_el2(void)
{
    return read_sysreg(mdcr_el2);
}