Re: [PATCH V2 7/8] vfio/pci: Support dynamic MSI-x

[kernel test robot <lkp@intel.com>]

Hi Reinette,

I love your patch! Yet something to improve:

[auto build test ERROR on 197b6b60ae7bc51dd0814953c562833143b292aa]

url:    https://github.com/intel-lab-lkp/linux/commits/Reinette-Chatre/vfio-pci-Consolidate-irq-cleanup-on-MSI-MSI-X-disable/20230329-055735
base:   197b6b60ae7bc51dd0814953c562833143b292aa
patch link:    https://lore.kernel.org/r/419f3ba2f732154d8ae079b3deb02d0fdbe3e258.1680038771.git.reinette.chatre%40intel.com
patch subject: [PATCH V2 7/8] vfio/pci: Support dynamic MSI-x
config: i386-randconfig-a001-20230327 (https://download.01.org/0day-ci/archive/20230329/202303291000.PWFqGCxH-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-8) 11.3.0
reproduce (this is a W=1 build):
        # https://github.com/intel-lab-lkp/linux/commit/420198d6ba9227a0ef81a2192ca35019fa6439cf
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Reinette-Chatre/vfio-pci-Consolidate-irq-cleanup-on-MSI-MSI-X-disable/20230329-055735
        git checkout 420198d6ba9227a0ef81a2192ca35019fa6439cf
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/vfio/pci/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202303291000.PWFqGCxH-lkp@intel.com/

All errors (new ones prefixed by >>):

   drivers/vfio/pci/vfio_pci_intrs.c: In function 'vfio_msi_set_vector_signal':
>> drivers/vfio/pci/vfio_pci_intrs.c:427:21: error: implicit declaration of function 'pci_msix_can_alloc_dyn' [-Werror=implicit-function-declaration]
     427 |         if (msix && pci_msix_can_alloc_dyn(vdev->pdev))
         |                     ^~~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/pci_msix_can_alloc_dyn +427 drivers/vfio/pci/vfio_pci_intrs.c

   413	
   414	static int vfio_msi_set_vector_signal(struct vfio_pci_core_device *vdev,
   415					      unsigned int vector, int fd, bool msix)
   416	{
   417		struct pci_dev *pdev = vdev->pdev;
   418		struct vfio_pci_irq_ctx *ctx;
   419		struct msi_map msix_map = {};
   420		bool allow_dyn_alloc = false;
   421		struct eventfd_ctx *trigger;
   422		bool new_ctx = false;
   423		int irq, ret;
   424		u16 cmd;
   425	
   426		/* Only MSI-X allows dynamic allocation. */
 > 427		if (msix && pci_msix_can_alloc_dyn(vdev->pdev))
   428			allow_dyn_alloc = true;
   429	
   430		ctx = vfio_irq_ctx_get(vdev, vector);
   431		if (!ctx && !allow_dyn_alloc)
   432			return -EINVAL;
   433	
   434		irq = pci_irq_vector(pdev, vector);
   435		/* Context and interrupt are always allocated together. */
   436		WARN_ON((ctx && irq == -EINVAL) || (!ctx && irq != -EINVAL));
   437	
   438		if (ctx && ctx->trigger) {
   439			irq_bypass_unregister_producer(&ctx->producer);
   440	
   441			cmd = vfio_pci_memory_lock_and_enable(vdev);
   442			free_irq(irq, ctx->trigger);
   443			if (allow_dyn_alloc) {
   444				msix_map.index = vector;
   445				msix_map.virq = irq;
   446				pci_msix_free_irq(pdev, msix_map);
   447				irq = -EINVAL;
   448			}
   449			vfio_pci_memory_unlock_and_restore(vdev, cmd);
   450			kfree(ctx->name);
   451			eventfd_ctx_put(ctx->trigger);
   452			ctx->trigger = NULL;
   453			if (allow_dyn_alloc) {
   454				vfio_irq_ctx_free(vdev, ctx, vector);
   455				ctx = NULL;
   456			}
   457		}
   458	
   459		if (fd < 0)
   460			return 0;
   461	
   462		if (!ctx) {
   463			ctx = vfio_irq_ctx_alloc_single(vdev, vector);
   464			if (!ctx)
   465				return -ENOMEM;
   466			new_ctx = true;
   467		}
   468	
   469		ctx->name = kasprintf(GFP_KERNEL_ACCOUNT, "vfio-msi%s[%d](%s)",
   470				      msix ? "x" : "", vector, pci_name(pdev));
   471		if (!ctx->name) {
   472			ret = -ENOMEM;
   473			goto out_free_ctx;
   474		}
   475	
   476		trigger = eventfd_ctx_fdget(fd);
   477		if (IS_ERR(trigger)) {
   478			ret = PTR_ERR(trigger);
   479			goto out_free_name;
   480		}
   481	
   482		cmd = vfio_pci_memory_lock_and_enable(vdev);
   483		if (msix) {
   484			if (irq == -EINVAL) {
   485				msix_map = pci_msix_alloc_irq_at(pdev, vector, NULL);
   486				if (msix_map.index < 0) {
   487					vfio_pci_memory_unlock_and_restore(vdev, cmd);
   488					ret = msix_map.index;
   489					goto out_put_eventfd_ctx;
   490				}
   491				irq = msix_map.virq;
   492			} else {
   493				/*
   494				 * The MSIx vector table resides in device memory which
   495				 * may be cleared via backdoor resets. We don't allow
   496				 * direct access to the vector table so even if a
   497				 * userspace driver attempts to save/restore around
   498				 * such a reset it would be unsuccessful. To avoid
   499				 * this, restore the cached value of the message prior
   500				 * to enabling.
   501				 */
   502				struct msi_msg msg;
   503	
   504				get_cached_msi_msg(irq, &msg);
   505				pci_write_msi_msg(irq, &msg);
   506			}
   507		}
   508	
   509		ret = request_irq(irq, vfio_msihandler, 0, ctx->name, trigger);
   510		if (ret)
   511			goto out_free_irq_locked;
   512	
   513		vfio_pci_memory_unlock_and_restore(vdev, cmd);
   514	
   515		ctx->producer.token = trigger;
   516		ctx->producer.irq = irq;
   517		ret = irq_bypass_register_producer(&ctx->producer);
   518		if (unlikely(ret)) {
   519			dev_info(&pdev->dev,
   520			"irq bypass producer (token %p) registration fails: %d\n",
   521			ctx->producer.token, ret);
   522	
   523			ctx->producer.token = NULL;
   524		}
   525		ctx->trigger = trigger;
   526	
   527		return 0;
   528	
   529	out_free_irq_locked:
   530		if (allow_dyn_alloc && new_ctx) {
   531			msix_map.index = vector;
   532			msix_map.virq = irq;
   533			pci_msix_free_irq(pdev, msix_map);
   534		}
   535		vfio_pci_memory_unlock_and_restore(vdev, cmd);
   536	out_put_eventfd_ctx:
   537		eventfd_ctx_put(trigger);
   538	out_free_name:
   539		kfree(ctx->name);
   540		ctx->name = NULL;
   541	out_free_ctx:
   542		if (allow_dyn_alloc && new_ctx)
   543			vfio_irq_ctx_free(vdev, ctx, vector);
   544		return ret;
   545	}
   546	

-- 
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https://github.com/intel/lkp-tests