Re: [PATCH v2 10/10] IOMMU: Add intel iommu irq-remapping and dmar hotplug support

[Yijing Wang <wangyijing@huawei.com>]

Hi Yinghai,
   Maybe we should add some guards to protect from initializing DMAR when we disable Intel IOMMU
like append intel_iommu=off to boot command.

Thanks!
Yijing.

On 2014/1/3 8:08, Yinghai Lu wrote:
> during hostbridge hotadd/hotremove, we call acpi_pci_iommu_add/remove in
> acpi_pci_root_add/remove.
> 
> For add, need to after ioapic add.
> 
> Run dsm in acpi root device to get iommu entries, and init dmar/irq_remapping
> 
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> Cc: Len Brown <lenb@kernel.org>
> Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Joerg Roedel <joro@8bytes.org>
> Cc: Donald Dutile <ddutile@redhat.com>
> Cc: linux-acpi@vger.kernel.org
> Cc: linux-pci@vger.kernel.org
> ---
>  drivers/acpi/pci_root.c  |   2 +
>  drivers/iommu/dmar.c     | 201 +++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/pci-acpi.h |   8 ++
>  3 files changed, 211 insertions(+)
> 
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index e666be3..dd82d8b 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -600,6 +600,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
>  	}
>  
>  	acpi_pci_ioapic_add(root);
> +	acpi_pci_iommu_add(root);
>  
>  	pci_bus_add_devices(root->bus);
>  	return 1;
> @@ -615,6 +616,7 @@ static void acpi_pci_root_remove(struct acpi_device *device)
>  
>  	pci_stop_root_bus(root->bus);
>  
> +	acpi_pci_iommu_remove(root);
>  	acpi_pci_ioapic_remove(root);
>  
>  	device_set_run_wake(root->bus->bridge, false);
> diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
> index 31d7942..c74f112 100644
> --- a/drivers/iommu/dmar.c
> +++ b/drivers/iommu/dmar.c
> @@ -38,6 +38,7 @@
>  #include <linux/tboot.h>
>  #include <linux/dmi.h>
>  #include <linux/slab.h>
> +#include <acpi/acpi.h>
>  #include <asm/irq_remapping.h>
>  #include <asm/iommu_table.h>
>  
> @@ -1548,3 +1549,203 @@ int __init dmar_ir_support(void)
>  	return dmar->flags & 0x1;
>  }
>  IOMMU_INIT_POST(detect_intel_iommu);
> +
> +static u8 dmar_uuid_str[] = "D8C1A3A6-BE9B-4C9B-91BF-C3CB81FC5DAF";
> +
> +static int acpi_dmar_dsm_support(acpi_handle handle)
> +{
> +	int support = 0;
> +	struct acpi_dsm_context context = {
> +		.uuid_str = dmar_uuid_str,
> +		.rev = 1,
> +		.func_idx = 0,
> +	};
> +
> +	if (ACPI_SUCCESS(acpi_run_dsm(handle, &context))) {
> +		u32 *ret = context.ret.pointer;
> +		support = ret[0];
> +		kfree(context.ret.pointer);
> +	}
> +
> +	if (support & 1)
> +		return support & 0x0e;
> +
> +	return 0;
> +}
> +
> +static void *acpi_dmar_dsm_run(acpi_handle handle, int idx)
> +{
> +	struct acpi_dsm_context context = {
> +		.uuid_str = dmar_uuid_str,
> +		.rev = 1,
> +		.func_idx = idx,
> +	};
> +
> +	if (ACPI_SUCCESS(acpi_run_dsm(handle, &context)))
> +		return context.ret.pointer;
> +
> +	return NULL;
> +}
> +
> +static void handle_iommu_add(acpi_handle handle, void **d, void **a)
> +{
> +	int support;
> +	struct acpi_dmar_header *header;
> +	struct dmar_drhd_unit *dmaru = NULL;
> +	struct dmar_atsr_unit *atsru = NULL;
> +
> +	*d = NULL;
> +	*a = NULL;
> +
> +	support = acpi_dmar_dsm_support(handle);
> +
> +	if (!support)
> +		return;
> +
> +	/* DRHD */
> +	if (support & (1<<1)) {
> +		header = acpi_dmar_dsm_run(handle, 1);
> +		dmar_table_print_dmar_entry(header);
> +		__dmar_parse_one_drhd(header, &dmaru);
> +	}
> +
> +	if (!dmaru)
> +		return;
> +
> +	/* ATSR */
> +	if (support & (1<<2)) {
> +		header = acpi_dmar_dsm_run(handle, 2);
> +		dmar_table_print_dmar_entry(header);
> +		__dmar_parse_one_atsr(header, &atsru);
> +	}
> +
> +	/* RHSA */
> +	if (support & (1<<3)) {
> +		header = acpi_dmar_dsm_run(handle, 3);
> +		dmar_table_print_dmar_entry(header);
> +		dmar_parse_one_rhsa(header);
> +		kfree(header);
> +	}
> +
> +	/*
> +	 *  only need to init intr_remap and dmar for hot-add ones
> +	 *  after enable_IR() or pci_iommu_init
> +	 */
> +	/*
> +	 * TODO: handle parsing failure for pre-installed hotplug one
> +	 *	Could make every parse_one duplicate the entry table?
> +	 */
> +	if (irq_remapping_enabled == 1)
> +		intel_enable_irq_remapping_one(dmaru);
> +	if (irq_remapping_enabled == 1 || intel_iommu_enabled == 1)
> +		dmar_parse_dev(dmaru);
> +	if (intel_iommu_enabled == 1) {
> +		init_dmar_one(dmaru);
> +		if (atsru) {
> +			header = atsru->hdr;
> +			if (atsr_parse_dev(atsru)) {
> +				kfree(header);
> +				atsru = NULL;
> +			}
> +			*a = atsru;
> +		}
> +	}
> +	*d = dmaru;
> +}
> +
> +static void handle_iommu_remove(void *drhd, void *atsr)
> +{
> +	struct dmar_drhd_unit *dmaru = drhd;
> +	struct dmar_atsr_unit *atsru = atsr;
> +
> +	if (!dmaru)
> +		return;
> +
> +	if (irq_remapping_enabled == 1)
> +		disable_irq_remapping_one(dmaru);
> +	if (intel_iommu_enabled == 1) {
> +		free_dmar_iommu(dmaru->iommu);
> +		if (atsru) {
> +			kfree(atsru->devices);
> +			remove_atsru_from_saved_dev_atsru_list(atsru);
> +		}
> +	}
> +	if (irq_remapping_enabled == 1 || intel_iommu_enabled == 1) {
> +		kfree(dmaru->devices);
> +		remove_dmaru_from_saved_dev_drhd_list(dmaru);
> +	}
> +	if (atsru) {
> +		kfree(atsru->hdr);
> +		list_del(&atsru->list);
> +		kfree(atsru);
> +	}
> +	free_iommu(dmaru->iommu);
> +	kfree(dmaru->hdr);
> +	list_del(&dmaru->list);
> +	kfree(dmaru);
> +}
> +
> +struct acpi_pci_iommu {
> +	acpi_handle root_handle;
> +	void *dmaru;
> +	void *atsru;
> +	struct list_head list;
> +};
> +
> +static LIST_HEAD(iommu_list);
> +static DEFINE_MUTEX(iommu_list_lock);
> +
> +static acpi_status register_iommu(acpi_handle handle, u32 lvl,
> +				  void *context, void **rv)
> +{
> +	acpi_handle root_handle = context;
> +	void *dmaru, *atsru;
> +	struct acpi_pci_iommu *iommu;
> +
> +	handle_iommu_add(handle, &dmaru, &atsru);
> +	if (!dmaru)
> +		return AE_OK;
> +
> +	iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
> +	if (!iommu) {
> +		pr_err("%s: cannot allocate memory\n", __func__);
> +		handle_iommu_remove(dmaru, atsru);
> +		return AE_OK;
> +	}
> +	iommu->root_handle = root_handle;
> +	iommu->dmaru = dmaru;
> +	iommu->atsru = atsru;
> +
> +	mutex_lock(&iommu_list_lock);
> +	list_add(&iommu->list, &iommu_list);
> +	mutex_unlock(&iommu_list_lock);
> +
> +	return AE_OK;
> +}
> +
> +void acpi_pci_iommu_add(struct acpi_pci_root *root)
> +{
> +	acpi_status status;
> +
> +	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, root->device->handle,
> +				     (u32)1, register_iommu, NULL,
> +				     root->device->handle,
> +				     NULL);
> +	if (ACPI_FAILURE(status))
> +		pr_err("%s: register_iommu failure - %d", __func__, status);
> +}
> +
> +void acpi_pci_iommu_remove(struct acpi_pci_root *root)
> +{
> +	struct acpi_pci_iommu *iommu, *tmp;
> +
> +	mutex_lock(&iommu_list_lock);
> +	list_for_each_entry_safe(iommu, tmp, &iommu_list, list) {
> +		if (root->device->handle != iommu->root_handle)
> +			continue;
> +		list_del(&iommu->list);
> +		handle_iommu_remove(iommu->dmaru, iommu->atsru);
> +		kfree(iommu);
> +	}
> +	mutex_unlock(&iommu_list_lock);
> +}
> diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
> index d2a976a..f00a89f 100644
> --- a/include/linux/pci-acpi.h
> +++ b/include/linux/pci-acpi.h
> @@ -86,4 +86,12 @@ extern bool aer_acpi_firmware_first(void);
>  static inline bool aer_acpi_firmware_first(void) { return false; }
>  #endif
>  
> +#ifdef CONFIG_DMAR_TABLE
> +void acpi_pci_iommu_add(struct acpi_pci_root *root);
> +void acpi_pci_iommu_remove(struct acpi_pci_root *root);
> +#else
> +static inline void acpi_pci_iommu_add(struct acpi_pci_root *root) { }
> +static inline void acpi_pci_iommu_remove(struct acpi_pci_root *root) { }
> +#endif
> +
>  #endif	/* _PCI_ACPI_H_ */
> 


-- 
Thanks!
Yijing