diff options
| author | Marc Zyngier <maz@kernel.org> | 2024-10-02 23:49:59 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2024-10-08 18:44:27 +0300 |
| commit | 1442ee0011983f0c5c4b92380e6853afb513841a (patch) | |
| tree | 78f047d12e66129a3021e639081e7974e020fe22 | |
| parent | 6eabf656048d904d961584de2e1d45bc0854f9fb (diff) | |
| download | linux-1442ee0011983f0c5c4b92380e6853afb513841a.tar.xz | |
irqchip/gic-v4: Don't allow a VMOVP on a dying VPE
Kunkun Jiang reported that there is a small window of opportunity for
userspace to force a change of affinity for a VPE while the VPE has already
been unmapped, but the corresponding doorbell interrupt still visible in
/proc/irq/.
Plug the race by checking the value of vmapp_count, which tracks whether
the VPE is mapped ot not, and returning an error in this case.
This involves making vmapp_count common to both GICv4.1 and its v4.0
ancestor.
Fixes: 64edfaa9a234 ("irqchip/gic-v4.1: Implement the v4.1 flavour of VMAPP")
Reported-by: Kunkun Jiang <jiangkunkun@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/c182ece6-2ba0-ce4f-3404-dba7a3ab6c52@huawei.com
Link: https://lore.kernel.org/all/20241002204959.2051709-1-maz@kernel.org
| -rw-r--r-- | drivers/irqchip/irq-gic-v3-its.c | 18 | ||||
| -rw-r--r-- | include/linux/irqchip/arm-gic-v4.h | 4 |
2 files changed, 15 insertions, 7 deletions
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c index fdec478ba5e7..ab597e74ba08 100644 --- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -797,8 +797,8 @@ static struct its_vpe *its_build_vmapp_cmd(struct its_node *its, its_encode_valid(cmd, desc->its_vmapp_cmd.valid); if (!desc->its_vmapp_cmd.valid) { + alloc = !atomic_dec_return(&desc->its_vmapp_cmd.vpe->vmapp_count); if (is_v4_1(its)) { - alloc = !atomic_dec_return(&desc->its_vmapp_cmd.vpe->vmapp_count); its_encode_alloc(cmd, alloc); /* * Unmapping a VPE is self-synchronizing on GICv4.1, @@ -817,13 +817,13 @@ static struct its_vpe *its_build_vmapp_cmd(struct its_node *its, its_encode_vpt_addr(cmd, vpt_addr); its_encode_vpt_size(cmd, LPI_NRBITS - 1); + alloc = !atomic_fetch_inc(&desc->its_vmapp_cmd.vpe->vmapp_count); + if (!is_v4_1(its)) goto out; vconf_addr = virt_to_phys(page_address(desc->its_vmapp_cmd.vpe->its_vm->vprop_page)); - alloc = !atomic_fetch_inc(&desc->its_vmapp_cmd.vpe->vmapp_count); - its_encode_alloc(cmd, alloc); /* @@ -3807,6 +3807,13 @@ static int its_vpe_set_affinity(struct irq_data *d, unsigned long flags; /* + * Check if we're racing against a VPE being destroyed, for + * which we don't want to allow a VMOVP. + */ + if (!atomic_read(&vpe->vmapp_count)) + return -EINVAL; + + /* * Changing affinity is mega expensive, so let's be as lazy as * we can and only do it if we really have to. Also, if mapped * into the proxy device, we need to move the doorbell @@ -4463,9 +4470,8 @@ static int its_vpe_init(struct its_vpe *vpe) raw_spin_lock_init(&vpe->vpe_lock); vpe->vpe_id = vpe_id; vpe->vpt_page = vpt_page; - if (gic_rdists->has_rvpeid) - atomic_set(&vpe->vmapp_count, 0); - else + atomic_set(&vpe->vmapp_count, 0); + if (!gic_rdists->has_rvpeid) vpe->vpe_proxy_event = -1; return 0; diff --git a/include/linux/irqchip/arm-gic-v4.h b/include/linux/irqchip/arm-gic-v4.h index ecabed6d3307..7f1f11a5e4e4 100644 --- a/include/linux/irqchip/arm-gic-v4.h +++ b/include/linux/irqchip/arm-gic-v4.h @@ -66,10 +66,12 @@ struct its_vpe { bool enabled; bool group; } sgi_config[16]; - atomic_t vmapp_count; }; }; + /* Track the VPE being mapped */ + atomic_t vmapp_count; + /* * Ensures mutual exclusion between affinity setting of the * vPE and vLPI operations using vpe->col_idx. |