From: Liu Yi L <yi.l.liu@intel.com>
To: alex.williamson@redhat.com, kwankhede@nvidia.com
Cc: kevin.tian@intel.com, baolu.lu@linux.intel.com,
yi.l.liu@intel.com, yi.y.sun@intel.com, joro@8bytes.org,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
yan.y.zhao@intel.com, shaopeng.he@intel.com,
chenbo.xia@intel.com, jun.j.tian@intel.com
Subject: [PATCH v2 08/13] vfio/pci: protect cap/ecap_perm bits alloc/free with atomic op
Date: Thu, 5 Sep 2019 15:59:25 +0800 [thread overview]
Message-ID: <1567670370-4484-9-git-send-email-yi.l.liu@intel.com> (raw)
In-Reply-To: <1567670370-4484-1-git-send-email-yi.l.liu@intel.com>
There is a case in which cap_perms and ecap_perms can be reallocated
by different modules. e.g. the vfio-mdev-pci sample driver. To secure
the initialization of cap_perms and ecap_perms, this patch adds an
atomic variable to track the user of cap/ecap_perms bits. First caller
of vfio_pci_init_perm_bits() will initialize the bits. While the last
caller of vfio_pci_uninit_perm_bits() will free the bits.
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
---
drivers/vfio/pci/vfio_pci_config.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index f0891bd..1b3e6e5 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -992,11 +992,17 @@ static int __init init_pci_ext_cap_pwr_perm(struct perm_bits *perm)
return 0;
}
+/* Track the user number of the cap/ecap perm_bits */
+atomic_t vfio_pci_perm_bits_users = ATOMIC_INIT(0);
+
/*
* Initialize the shared permission tables
*/
void vfio_pci_uninit_perm_bits(void)
{
+ if (atomic_dec_return(&vfio_pci_perm_bits_users))
+ return;
+
free_perm_bits(&cap_perms[PCI_CAP_ID_BASIC]);
free_perm_bits(&cap_perms[PCI_CAP_ID_PM]);
@@ -1013,6 +1019,9 @@ int __init vfio_pci_init_perm_bits(void)
{
int ret;
+ if (atomic_inc_return(&vfio_pci_perm_bits_users) != 1)
+ return 0;
+
/* Basic config space */
ret = init_pci_cap_basic_perm(&cap_perms[PCI_CAP_ID_BASIC]);
--
2.7.4
next prev parent reply other threads:[~2019-09-06 8:18 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-05 7:59 [PATCH v2 00/13] vfio_pci: wrap pci device as a mediated device Liu Yi L
2019-09-05 7:59 ` [PATCH v2 01/13] vfio_pci: move vfio_pci_is_vga/vfio_vga_disabled to header Liu Yi L
2019-09-05 7:59 ` [PATCH v2 02/13] vfio_pci: refine user config reference in vfio-pci module Liu Yi L
2019-09-26 2:36 ` Alex Williamson
2019-09-30 12:38 ` Liu, Yi L
2019-09-05 7:59 ` [PATCH v2 03/13] vfio_pci: refine vfio_pci_driver reference in vfio_pci.c Liu Yi L
2019-09-05 7:59 ` [PATCH v2 04/13] vfio_pci: make common functions be extern Liu Yi L
2019-09-05 7:59 ` [PATCH v2 05/13] vfio_pci: duplicate vfio_pci.c Liu Yi L
2019-09-05 7:59 ` [PATCH v2 06/13] vfio_pci: shrink vfio_pci_common.c Liu Yi L
2019-09-05 7:59 ` [PATCH v2 07/13] vfio_pci: shrink vfio_pci.c Liu Yi L
2019-09-05 7:59 ` Liu Yi L [this message]
2019-09-26 2:36 ` [PATCH v2 08/13] vfio/pci: protect cap/ecap_perm bits alloc/free with atomic op Alex Williamson
2019-09-30 12:38 ` Liu, Yi L
2019-09-05 7:59 ` [PATCH v2 09/13] samples: add vfio-mdev-pci driver Liu Yi L
2019-09-05 7:59 ` [PATCH v2 10/13] samples: refine " Liu Yi L
2019-09-26 2:36 ` Alex Williamson
2019-09-30 12:39 ` Liu, Yi L
2019-09-05 7:59 ` [PATCH v2 11/13] samples/vfio-mdev-pci: call vfio_add_group_dev() Liu Yi L
2019-09-26 2:36 ` Alex Williamson
2019-09-30 12:40 ` Liu, Yi L
2019-09-05 7:59 ` [PATCH v2 12/13] vfio/type1: use iommu_attach_group() for wrapping PF/VF as mdev Liu Yi L
2019-09-26 2:37 ` Alex Williamson
2019-09-05 7:59 ` [PATCH v2 13/13] vfio/type1: track iommu backed group attach Liu Yi L
2019-09-25 9:13 ` [PATCH v2 00/13] vfio_pci: wrap pci device as a mediated device Liu, Yi L
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