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* Merge tag 'stable/for-linus-3.13-rc2-tag' of ↵Linus Torvalds2013-12-022-2/+9
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull Xen bug-fixes from Konrad Rzeszutek Wilk: "Fixes to patches that went in this merge window along with a latent bug: - Fix lazy flushing in case m2p override fails. - Fix module compile issues with ARM/Xen - Add missing call to DMA map page for Xen SWIOTLB for ARM" * tag 'stable/for-linus-3.13-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/gnttab: leave lazy MMU mode in the case of a m2p override failure xen/arm: p2m_init and p2m_lock should be static arm/xen: Export phys_to_mach to fix Xen module link errors swiotlb-xen: add missing xen_dma_map_page call
| * xen/gnttab: leave lazy MMU mode in the case of a m2p override failureMatt Wilson2013-11-261-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit f62805f1 introduced a bug where lazy MMU mode isn't exited if a m2p_add/remove_override call fails. Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Anthony Liguori <aliguori@amazon.com> Cc: xen-devel@lists.xenproject.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Matt Wilson <msw@amazon.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> CC: stable@vger.kernel.org
| * swiotlb-xen: add missing xen_dma_map_page callStefano Stabellini2013-11-151-0/+5
| | | | | | | | | | | | | | | | swiotlb-xen is missing a xen_dma_map_page call in xen_swiotlb_map_sg_attrs, in the bounce buffer path. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* | Merge tag 'pm+acpi-2-3.13-rc1' of ↵Linus Torvalds2013-11-201-3/+3
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull more ACPI and power management updates from Rafael Wysocki: - ACPI-based device hotplug fixes for issues introduced recently and a fix for an older error code path bug in the ACPI PCI host bridge driver - Fix for recently broken OMAP cpufreq build from Viresh Kumar - Fix for a recent hibernation regression related to s2disk - Fix for a locking-related regression in the ACPI EC driver from Puneet Kumar - System suspend error code path fix related to runtime PM and runtime PM documentation update from Ulf Hansson - cpufreq's conservative governor fix from Xiaoguang Chen - New processor IDs for intel_idle and turbostat and removal of an obsolete Kconfig option from Len Brown - New device IDs for the ACPI LPSS (Low-Power Subsystem) driver and ACPI-based PCI hotplug (ACPIPHP) cleanup from Mika Westerberg - Removal of several ACPI video DMI blacklist entries that are not necessary any more from Aaron Lu - Rework of the ACPI companion representation in struct device and code cleanup related to that change from Rafael J Wysocki, Lan Tianyu and Jarkko Nikula - Fixes for assigning names to ACPI-enumerated I2C and SPI devices from Jarkko Nikula * tag 'pm+acpi-2-3.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (24 commits) PCI / hotplug / ACPI: Drop unused acpiphp_debug declaration ACPI / scan: Set flags.match_driver in acpi_bus_scan_fixed() ACPI / PCI root: Clear driver_data before failing enumeration ACPI / hotplug: Fix PCI host bridge hot removal ACPI / hotplug: Fix acpi_bus_get_device() return value check cpufreq: governor: Remove fossil comment in the cpufreq_governor_dbs() ACPI / video: clean up DMI table for initial black screen problem ACPI / EC: Ensure lock is acquired before accessing ec struct members PM / Hibernate: Do not crash kernel in free_basic_memory_bitmaps() ACPI / AC: Remove struct acpi_device pointer from struct acpi_ac spi: Use stable dev_name for ACPI enumerated SPI slaves i2c: Use stable dev_name for ACPI enumerated I2C slaves ACPI: Provide acpi_dev_name accessor for struct acpi_device device name ACPI / bind: Use (put|get)_device() on ACPI device objects too ACPI: Eliminate the DEVICE_ACPI_HANDLE() macro ACPI / driver core: Store an ACPI device pointer in struct acpi_dev_node cpufreq: OMAP: Fix compilation error 'r & ret undeclared' PM / Runtime: Fix error path for prepare PM / Runtime: Update documentation around probe|remove|suspend cpufreq: conservative: set requested_freq to policy max when it is over policy max ...
| * | ACPI: Eliminate the DEVICE_ACPI_HANDLE() macroRafael J. Wysocki2013-11-141-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | Since DEVICE_ACPI_HANDLE() is now literally identical to ACPI_HANDLE(), replace it with the latter everywhere and drop its definition from include/acpi.h. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | Merge tag 'stable/for-linus-3.13-rc0-tag' of ↵Linus Torvalds2013-11-157-34/+162
|\ \ \ | |/ / |/| / | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull Xen updates from Konrad Rzeszutek Wilk: "This has tons of fixes and two major features which are concentrated around the Xen SWIOTLB library. The short <blurb> is that the tracing facility (just one function) has been added to SWIOTLB to make it easier to track I/O progress. Additionally under Xen and ARM (32 & 64) the Xen-SWIOTLB driver "is used to translate physical to machine and machine to physical addresses of foreign[guest] pages for DMA operations" (Stefano) when booting under hardware without proper IOMMU. There are also bug-fixes, cleanups, compile warning fixes, etc. The commit times for some of the commits is a bit fresh - that is b/c we wanted to make sure we have the Ack's from the ARM folks - which with the string of back-to-back conferences took a bit of time. Rest assured - the code has been stewing in #linux-next for some time. Features: - SWIOTLB has tracing added when doing bounce buffer. - Xen ARM/ARM64 can use Xen-SWIOTLB. This work allows Linux to safely program real devices for DMA operations when running as a guest on Xen on ARM, without IOMMU support. [*1] - xen_raw_printk works with PVHVM guests if needed. Bug-fixes: - Make memory ballooning work under HVM with large MMIO region. - Inform hypervisor of MCFG regions found in ACPI DSDT. - Remove deprecated IRQF_DISABLED. - Remove deprecated __cpuinit. [*1]: "On arm and arm64 all Xen guests, including dom0, run with second stage translation enabled. As a consequence when dom0 programs a device for a DMA operation is going to use (pseudo) physical addresses instead machine addresses. This work introduces two trees to track physical to machine and machine to physical mappings of foreign pages. Local pages are assumed mapped 1:1 (physical address == machine address). It enables the SWIOTLB-Xen driver on ARM and ARM64, so that Linux can translate physical addresses to machine addresses for dma operations when necessary. " (Stefano)" * tag 'stable/for-linus-3.13-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (32 commits) xen/arm: pfn_to_mfn and mfn_to_pfn return the argument if nothing is in the p2m arm,arm64/include/asm/io.h: define struct bio_vec swiotlb-xen: missing include dma-direction.h pci-swiotlb-xen: call pci_request_acs only ifdef CONFIG_PCI arm: make SWIOTLB available xen: delete new instances of added __cpuinit xen/balloon: Set balloon's initial state to number of existing RAM pages xen/mcfg: Call PHYSDEVOP_pci_mmcfg_reserved for MCFG areas. xen: remove deprecated IRQF_DISABLED x86/xen: remove deprecated IRQF_DISABLED swiotlb-xen: fix error code returned by xen_swiotlb_map_sg_attrs swiotlb-xen: static inline xen_phys_to_bus, xen_bus_to_phys, xen_virt_to_bus and range_straddles_page_boundary grant-table: call set_phys_to_machine after mapping grant refs arm,arm64: do not always merge biovec if we are running on Xen swiotlb: print a warning when the swiotlb is full swiotlb-xen: use xen_dma_map/unmap_page, xen_dma_sync_single_for_cpu/device xen: introduce xen_dma_map/unmap_page and xen_dma_sync_single_for_cpu/device tracing/events: Fix swiotlb tracepoint creation swiotlb-xen: use xen_alloc/free_coherent_pages xen: introduce xen_alloc/free_coherent_pages ...
| * Merge remote-tracking branch 'stefano/swiotlb-xen-9.1' into ↵Konrad Rzeszutek Wilk2013-11-083-29/+106
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | stable/for-linus-3.13 * stefano/swiotlb-xen-9.1: swiotlb-xen: fix error code returned by xen_swiotlb_map_sg_attrs swiotlb-xen: static inline xen_phys_to_bus, xen_bus_to_phys, xen_virt_to_bus and range_straddles_page_boundary grant-table: call set_phys_to_machine after mapping grant refs arm,arm64: do not always merge biovec if we are running on Xen swiotlb: print a warning when the swiotlb is full swiotlb-xen: use xen_dma_map/unmap_page, xen_dma_sync_single_for_cpu/device xen: introduce xen_dma_map/unmap_page and xen_dma_sync_single_for_cpu/device swiotlb-xen: use xen_alloc/free_coherent_pages xen: introduce xen_alloc/free_coherent_pages arm64/xen: get_dma_ops: return xen_dma_ops if we are running as xen_initial_domain arm/xen: get_dma_ops: return xen_dma_ops if we are running as xen_initial_domain swiotlb-xen: introduce xen_swiotlb_set_dma_mask xen/arm,arm64: enable SWIOTLB_XEN xen: make xen_create_contiguous_region return the dma address xen/x86: allow __set_phys_to_machine for autotranslate guests arm/xen,arm64/xen: introduce p2m arm64: define DMA_ERROR_CODE arm: make SWIOTLB available Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Conflicts: arch/arm/include/asm/dma-mapping.h drivers/xen/swiotlb-xen.c [Conflicts arose b/c "arm: make SWIOTLB available" v8 was in Stefano's branch, while I had v9 + Ack from Russel. I also fixed up white-space issues]
| | * swiotlb-xen: fix error code returned by xen_swiotlb_map_sg_attrsStefano Stabellini2013-10-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | map_sg returns the number of elements mapped, not a dma_addr_t. In case of error return 0, not DMA_ERROR_CODE. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
| | * swiotlb-xen: static inline xen_phys_to_bus, xen_bus_to_phys, xen_virt_to_bus ↵Stefano Stabellini2013-10-251-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | and range_straddles_page_boundary This functions are small and called frequently. Static inline them. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
| | * grant-table: call set_phys_to_machine after mapping grant refsStefano Stabellini2013-10-251-2/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When mapping/unmapping grant refs, call set_phys_to_machine to update the P2M with the new mappings for autotranslate guests. This is (almost) a nop on x86. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Changes in v9: - add in-code comments.
| | * swiotlb: print a warning when the swiotlb is fullStefano Stabellini2013-10-251-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Changes in v7: - use dev_warn instead of pr_warn.
| | * swiotlb-xen: use xen_dma_map/unmap_page, xen_dma_sync_single_for_cpu/deviceStefano Stabellini2013-10-251-8/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Call xen_dma_map_page, xen_dma_unmap_page, xen_dma_sync_single_for_cpu, xen_dma_sync_single_for_device from swiotlb-xen to ensure cpu/device coherency of the pages used for DMA, including the ones belonging to the swiotlb buffer. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
| | * swiotlb-xen: use xen_alloc/free_coherent_pagesStefano Stabellini2013-10-101-10/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use xen_alloc_coherent_pages and xen_free_coherent_pages to allocate or free coherent pages. We need to be careful handling the pointer returned by xen_alloc_coherent_pages, because on ARM the pointer is not equal to phys_to_virt(*dma_handle). In fact virt_to_phys only works for kernel direct mapped RAM memory. In ARM case the pointer could be an ioremap address, therefore passing it to virt_to_phys would give you another physical address that doesn't correspond to it. Make xen_create_contiguous_region take a phys_addr_t as start parameter to avoid the virt_to_phys calls which would be incorrect. Changes in v6: - remove extra spaces. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| | * swiotlb-xen: introduce xen_swiotlb_set_dma_maskStefano Stabellini2013-10-091-0/+12
| | | | | | | | | | | | | | | | | | Implement xen_swiotlb_set_dma_mask, use it for set_dma_mask on arm. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
| | * xen/arm,arm64: enable SWIOTLB_XENStefano Stabellini2013-10-102-1/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Xen on arm and arm64 needs SWIOTLB_XEN: when running on Xen we need to program the hardware with mfns rather than pfns for dma addresses. Remove SWIOTLB_XEN dependency on X86 and PCI and make XEN select SWIOTLB_XEN on arm and arm64. At the moment always rely on swiotlb-xen, but when Xen starts supporting hardware IOMMUs we'll be able to avoid it conditionally on the presence of an IOMMU on the platform. Implement xen_create_contiguous_region on arm and arm64: for the moment we assume that dom0 has been mapped 1:1 (physical addresses == machine addresses) therefore we don't need to call XENMEM_exchange. Simply return the physical address as dma address. Initialize the xen-swiotlb from xen_early_init (before the native dma_ops are initialized), set xen_dma_ops to &xen_swiotlb_dma_ops. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Changes in v8: - assume dom0 is mapped 1:1, no need to call XENMEM_exchange. Changes in v7: - call __set_phys_to_machine_multi from xen_create_contiguous_region and xen_destroy_contiguous_region to update the P2M; - don't call XENMEM_unpin, it has been removed; - call XENMEM_exchange instead of XENMEM_exchange_and_pin; - set nr_exchanged to 0 before calling the hypercall. Changes in v6: - introduce and export xen_dma_ops; - call xen_mm_init from as arch_initcall. Changes in v4: - remove redefinition of DMA_ERROR_CODE; - update the code to use XENMEM_exchange_and_pin and XENMEM_unpin; - add a note about hardware IOMMU in the commit message. Changes in v3: - code style changes; - warn on XENMEM_put_dma_buf failures.
| | * xen: make xen_create_contiguous_region return the dma addressStefano Stabellini2013-10-091-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Modify xen_create_contiguous_region to return the dma address of the newly contiguous buffer. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Changes in v4: - use virt_to_machine instead of virt_to_bus.
| * | xen: delete new instances of added __cpuinitPaul Gortmaker2013-11-081-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 6efa20e49b9cb1db1ab66870cc37323474a75a13 ("xen: Support 64-bit PV guest receiving NMIs") and commit cd9151e26d31048b2b5e00fd02e110e07d2200c9 ( "xen/balloon: set a mapping for ballooned out pages") added new instances of __cpuinit usage. We removed this a couple versions ago; we now want to remove the compat no-op stubs. Introducing new users is not what we want to see at this point in time, as it will break once the stubs are gone. Cc: Konrad Rzeszutek Wilk <konrad@kernel.org> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * | xen/balloon: Set balloon's initial state to number of existing RAM pagesBoris Ostrovsky2013-11-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently balloon's initial value is set to max_pfn which includes non-RAM ranges such as MMIO hole. As result, initial memory target (specified by guest's configuration file) will appear smaller than what balloon driver perceives to be the current number of available pages. Thus it will balloon down "extra" pages, decreasing amount of available memory for no good reason. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * | xen/mcfg: Call PHYSDEVOP_pci_mmcfg_reserved for MCFG areas.Konrad Rzeszutek Wilk2013-11-081-0/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The PCI MMCONFIG area is usually reserved via the E820 so the Xen hypervisor is aware of these regions. But they can also be enumerated in the ACPI DSDT which means the hypervisor won't know of them until the initial domain informs it of via PHYSDEVOP_pci_mmcfg_reserved. This is what this patch does for all of the MCFG regions that the initial domain is aware of (E820 enumerated and ACPI). Reported-by: Santosh Jodh <Santosh.Jodh@citrix.com> CC: Jan Beulich <JBeulich@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: David Vrabel <david.vrabel@citrix.com> CC: Mukesh Rathor <mukesh.rathor@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [v1: Redid it a bit] [v2: Dropped the P2M 1-1 setting] [v3: Check for Xen in-case we are running under baremetal] [v4: Wrap with CONFIG_PCI_MMCONFIG]
| * | xen: remove deprecated IRQF_DISABLEDMichael Opdenacker2013-11-062-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch proposes to remove the IRQF_DISABLED flag from drivers/xen code. It's a NOOP since 2.6.35 and it will be removed one day. Note that architecture dependent fixes for IRQF_DISABLED were already submitted through separate patches. Signed-off-by: Michael Opdenacker <michael.opdenacker@free-electrons.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * | tracing/events: Fix swiotlb tracepoint creationThierry Reding2013-10-241-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Tracepoints are only created when Xen support is enabled, but they are also referenced within lib/swiotlb.c. So unless Xen support is enabled the tracepoints will be missing, therefore causing builds to fail. Fix this by moving the tracepoint creation to lib/swiotlb.c, which works nicely because the Xen swiotlb support selects the generic swiotlb support. Signed-off-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * | tracing/events: Add bounce tracing to swiotblZoltan Kiss2013-10-021-0/+5
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ftrace is currently not able to detect when SWIOTLB has to do double buffering. Under Xen you can only see it indirectly in function_graph, when xen_swiotlb_map_page() doesn't stop after range_straddles_page_boundary(), but calls spinlock functions, memcpy() and xen_phys_to_bus() as well. This patch introduces the swiotlb:swiotlb_bounced event, which also prints out the following informations to help you find out why bouncing happened: dev_name: 0000:08:00.0 dma_mask=ffffffffffffffff dev_addr=9149f000 size=32768 swiotlb_force=0 If you use Xen, and (dev_addr + size + 1) > dma_mask, the buffer is out of the device's DMA range. If swiotlb_force == 1, you should really change the kernel parameters. Otherwise, the buffer is not contiguous in mfn space. Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> [v1: Don't print 'swiotlb_force=X', just print swiotlb_force if it is enabled] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* | xenbus: convert bus code to use dev_groupsGreg Kroah-Hartman2013-10-164-9/+21
|/ | | | | | | | | | | | The dev_attrs field of struct bus_type is going away soon, dev_groups should be used instead. This converts the xenbus code to use the correct field. Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: <xen-devel@lists.xenproject.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge tag 'stable/for-linus-3.12-rc2-tag' of ↵Linus Torvalds2013-09-251-12/+11
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull Xen fixes from Konrad Rzeszutek Wilk: "Bug-fixes and one update to the kernel-paramters.txt documentation. - Fix PV spinlocks triggering jump_label code bug - Remove extraneous code in the tpm front driver - Fix ballooning out of pages when non-preemptible - Fix deadlock when using a 32-bit initial domain with large amount of memory - Add xen_nopvpsin parameter to the documentation" * tag 'stable/for-linus-3.12-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/spinlock: Document the xen_nopvspin parameter. xen/p2m: check MFN is in range before using the m2p table xen/balloon: don't alloc page while non-preemptible xen: Do not enable spinlocks before jump_label_init() has executed tpm: xen-tpmfront: Remove the locality sysfs attribute tpm: xen-tpmfront: Fix default durations
| * xen/balloon: don't alloc page while non-preemptibleDavid Vrabel2013-09-241-12/+11
| | | | | | | | | | | | | | | | | | get_balloon_scratch_page() disables preemption so we cannot call alloc_page() in between get/put_balloon_scratch_page(). Shuffle bits around in decrease_reservation() to avoid this. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* | Merge tag 'stable/for-linus-3.12-rc0-tag-three' of ↵Linus Torvalds2013-09-121-6/+7
|\ \ | |/ | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull Xen balloon driver bug-fixes from Stefano Stabellini: - fix a preemption bug in xen/balloon.c; - remove an harmful BUG_ON in xen/balloon.c that can trigger in non-erroneous situations. * tag 'stable/for-linus-3.12-rc0-tag-three' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/balloon: remove BUG_ON in increase_reservation xen/balloon: ensure preemption is disabled when using a scratch page
| * xen/balloon: remove BUG_ON in increase_reservationWei Liu2013-09-111-2/+0
| | | | | | | | | | | | | | | | | | The BUG_ON in increase_reservation is wrong as we have P2M entry ballooned out page set to balloon scratch page, so it might have a valid P2M entry at that point. Signed-off-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
| * xen/balloon: ensure preemption is disabled when using a scratch pageDavid Vrabel2013-09-111-4/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | In decrease_reservation(), if the kernel is preempted between updating the mapping and updating the p2m then they may end up using different scratch pages. Use get_balloon_scratch_page() and put_balloon_scratch_page() which use get_cpu_var() and put_cpu_var() to correctly disable preemption. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
| * Merge tag 'v3.11-rc7' into stable/for-linus-3.12Konrad Rzeszutek Wilk2013-09-091-1/+12
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Linux 3.11-rc7 As we need the git commit 28817e9de4f039a1a8c1fe1df2fa2df524626b9e Author: Chuck Anderson <chuck.anderson@oracle.com> Date: Tue Aug 6 15:12:19 2013 -0700 xen/smp: initialize IPI vectors before marking CPU online * tag 'v3.11-rc7': (443 commits) Linux 3.11-rc7 ARC: [lib] strchr breakage in Big-endian configuration VFS: collect_mounts() should return an ERR_PTR bfs: iget_locked() doesn't return an ERR_PTR efs: iget_locked() doesn't return an ERR_PTR() proc: kill the extra proc_readfd_common()->dir_emit_dots() cope with potentially long ->d_dname() output for shmem/hugetlb usb: phy: fix build breakage USB: OHCI: add missing PCI PM callbacks to ohci-pci.c staging: comedi: bug-fix NULL pointer dereference on failed attach lib/lz4: correct the LZ4 license memcg: get rid of swapaccount leftovers nilfs2: fix issue with counting number of bio requests for BIO_EOPNOTSUPP error detection nilfs2: remove double bio_put() in nilfs_end_bio_write() for BIO_EOPNOTSUPP error drivers/platform/olpc/olpc-ec.c: initialise earlier ipv4: expose IPV4_DEVCONF ipv6: handle Redirect ICMP Message with no Redirected Header option be2net: fix disabling TX in be_close() Revert "ACPI / video: Always call acpi_video_init_brightness() on init" Revert "genetlink: fix family dump race" ... Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* | \ Merge tag 'stable/for-linus-3.12-rc0-tag' of ↵Linus Torvalds2013-09-048-142/+322
|\ \ \ | |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull Xen updates from Konrad Rzeszutek Wilk: "A couple of features and a ton of bug-fixes. There is also some maintership changes. Jeremy is enjoying the full-time work at the startup and as much as he would love to help - he can't find the time. I have a bunch of other things that I promised to work on - paravirt diet, get SWIOTLB working everywhere, etc, but haven't been able to find the time. As such both David Vrabel and Boris Ostrovsky have graciously volunteered to help with the maintership role. They will keep the lid on regressions, bug-fixes, etc. I will be in the background to help - but eventually there will be less of me doing the Xen GIT pulls and more of them. Stefano is still doing the ARM/ARM64 and will continue on doing so. Features: - Xen Trusted Platform Module (TPM) frontend driver - with the backend in MiniOS. - Scalability improvements in event channel. - Two extra Xen co-maintainers (David, Boris) and one going away (Jeremy) Bug-fixes: - Make the 1:1 mapping work during early bootup on selective regions. - Add scratch page to balloon driver to deal with unexpected code still holding on stale pages. - Allow NMIs on PV guests (64-bit only) - Remove unnecessary TLB flush in M2P code. - Fixes duplicate callbacks in Xen granttable code. - Fixes in PRIVCMD_MMAPBATCH ioctls to allow retries - Fix for events being lost due to rescheduling on different VCPUs. - More documentation" * tag 'stable/for-linus-3.12-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (23 commits) hvc_xen: Remove unnecessary __GFP_ZERO from kzalloc drivers/xen-tpmfront: Fix compile issue with missing option. xen/balloon: don't set P2M entry for auto translated guest xen/evtchn: double free on error Xen: Fix retry calls into PRIVCMD_MMAPBATCH*. xen/pvhvm: Initialize xen panic handler for PVHVM guests xen/m2p: use GNTTABOP_unmap_and_replace to reinstate the original mapping xen: fix ARM build after 6efa20e4 MAINTAINERS: Remove Jeremy from the Xen subsystem. xen/events: document behaviour when scanning the start word for events x86/xen: during early setup, only 1:1 map the ISA region x86/xen: disable premption when enabling local irqs swiotlb-xen: replace dma_length with sg_dma_len() macro swiotlb: replace dma_length with sg_dma_len() macro xen/balloon: set a mapping for ballooned out pages xen/evtchn: improve scalability by using per-user locks xen/p2m: avoid unneccesary TLB flush in m2p_remove_override() MAINTAINERS: Add in two extra co-maintainers of the Xen tree. MAINTAINERS: Update the Xen subsystem's with proper mailing list. xen: replace strict_strtoul() with kstrtoul() ...
| * | xen/balloon: don't set P2M entry for auto translated guestWei Liu2013-08-301-2/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In commit cd9151e2: xen/balloon: set a mapping for ballooned out pages we have the ballooned out page's mapping set to a scratch page. That commit also sets the P2M entry of ballooned out page to the scratch page's MFN. This is necessary for PV guest but not for HVM guest. On the other hand, setting the P2M entry would trigger BUG_ON in __set_phys_to_machine. The correct thing to do here is to avoid calling __set_phys_to_machine for auto translated guest. Signed-off-by: Wei Liu <wei.liu2@citrix.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
| * | xen/evtchn: double free on errorDan Carpenter2013-08-301-1/+0
| | | | | | | | | | | | | | | | | | | | | The call to del_evtchn() frees "evtchn". Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * | Xen: Fix retry calls into PRIVCMD_MMAPBATCH*.Andres Lagar-Cavilla2013-08-301-20/+63
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a foreign mapper attempts to map guest frames that are paged out, the mapper receives an ENOENT response and will have to try again while a helper process pages the target frame back in. Gating checks on PRIVCMD_MMAPBATCH* ioctl args were preventing retries of mapping calls. Permit subsequent calls to update a sub-range of the VMA, iff nothing is yet mapped in that range. Since it is now valid to call PRIVCMD_MMAPBATCH* multiple times, only set vma->vm_private_data if the parameters are valid and (if necessary) the pages for the auto_translated_physmap case have been allocated. This prevents subsequent calls from incorrectly entering the 'retry' path when there are no pages allocated etc. Signed-off-by: Andres Lagar-Cavilla <andres@lagarcavilla.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * | xen/m2p: use GNTTABOP_unmap_and_replace to reinstate the original mappingStefano Stabellini2013-08-201-9/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | GNTTABOP_unmap_grant_ref unmaps a grant and replaces it with a 0 mapping instead of reinstating the original mapping. Doing so separately would be racy. To unmap a grant and reinstate the original mapping atomically we use GNTTABOP_unmap_and_replace. GNTTABOP_unmap_and_replace doesn't work with GNTMAP_contains_pte, so don't use it for kmaps. GNTTABOP_unmap_and_replace zeroes the mapping passed in new_addr so we have to reinstate it, however that is a per-cpu mapping only used for balloon scratch pages, so we can be sure that it's not going to be accessed while the mapping is not valid. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> CC: alex@alex.org.uk CC: dcrisan@flexiant.com [v1: Konrad fixed up the conflicts] Conflicts: arch/x86/xen/p2m.c
| * | xen: fix ARM build after 6efa20e4Stefano Stabellini2013-08-201-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following commit: commit 6efa20e49b9cb1db1ab66870cc37323474a75a13 Author: Konrad Rzeszutek Wilk <konrad@kernel.org> Date: Fri Jul 19 11:51:31 2013 -0400 xen: Support 64-bit PV guest receiving NMIs breaks the Xen ARM build: CC drivers/xen/events.o drivers/xen/events.c: In function 'xen_send_IPI_one': drivers/xen/events.c:1218:6: error: 'XEN_NMI_VECTOR' undeclared (first use in this function) Simply ifdef the undeclared symbol in the code. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
| * | xen/events: document behaviour when scanning the start word for eventsDavid Vrabel2013-08-201-5/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The original comment on the scanning of the start word on the 2nd pass did not reflect the actual behaviour (the code was incorrectly masking bit_idx instead of the pending word itself). The documented behaviour is not actually required since if event were pending in the MSBs, they would be immediately scanned anyway as we go through the loop again. Update the documentation to reflect this (instead of trying to change the behaviour). Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
| * | swiotlb-xen: replace dma_length with sg_dma_len() macroStefano Stabellini2013-08-091-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | swiotlb-xen has an implicit dependency on CONFIG_NEED_SG_DMA_LENGTH. Remove it by replacing dma_length with sg_dma_len. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * | xen/balloon: set a mapping for ballooned out pagesStefano Stabellini2013-08-091-3/+66
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently ballooned out pages are mapped to 0 and have INVALID_P2M_ENTRY in the p2m. These ballooned out pages are used to map foreign grants by gntdev and blkback (see alloc_xenballooned_pages). Allocate a page per cpu and map all the ballooned out pages to the corresponding mfn. Set the p2m accordingly. This way reading from a ballooned out page won't cause a kernel crash (see http://lists.xen.org/archives/html/xen-devel/2012-12/msg01154.html). Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> CC: alex@alex.org.uk CC: dcrisan@flexiant.com Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * | xen/evtchn: improve scalability by using per-user locksDavid Vrabel2013-08-091-80/+112
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The global array of port users and the port_user_lock limits scalability of the evtchn device. Instead of the global array lookup, use a per-use (per-fd) tree of event channels bound by that user and protect the tree with a per-user lock. This is also a prerequiste for extended the number of supported event channels, by removing the fixed size, per-event channel array. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * | xen: replace strict_strtoul() with kstrtoul()Jingoo Han2013-08-091-18/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | The usage of strict_strtoul() is not preferred, because strict_strtoul() is obsolete. Thus, kstrtoul() should be used. Signed-off-by: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * | xen-gnt: prevent adding duplicate gnt callbacksRoger Pau Monne2013-08-091-2/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the current implementation, the callback in the tail of the list can be added twice, because the check done in gnttab_request_free_callback is bogus, callback->next can be NULL if it is the last callback in the list. If we add the same callback twice we end up with an infinite loop, were callback == callback->next. Replace this check with a proper one that iterates over the list to see if the callback has already been added. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Matt Wilson <msw@amazon.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> CC: stable@vger.kernel.org
| * | xen: Support 64-bit PV guest receiving NMIsKonrad Rzeszutek Wilk2013-08-091-1/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is based on a patch that Zhenzhong Duan had sent - which was missing some of the remaining pieces. The kernel has the logic to handle Xen-type-exceptions using the paravirt interface in the assembler code (see PARAVIRT_ADJUST_EXCEPTION_FRAME - pv_irq_ops.adjust_exception_frame and and INTERRUPT_RETURN - pv_cpu_ops.iret). That means the nmi handler (and other exception handlers) use the hypervisor iret. The other changes that would be neccessary for this would be to translate the NMI_VECTOR to one of the entries on the ipi_vector and make xen_send_IPI_mask_allbutself use different events. Fortunately for us commit 1db01b4903639fcfaec213701a494fe3fb2c490b (xen: Clean up apic ipi interface) implemented this and we piggyback on the cleanup such that the apic IPI interface will pass the right vector value for NMI. With this patch we can trigger NMIs within a PV guest (only tested x86_64). For this to work with normal PV guests (not initial domain) we need the domain to be able to use the APIC ops - they are already implemented to use the Xen event channels. For that to be turned on in a PV domU we need to remove the masking of X86_FEATURE_APIC. Incidentally that means kgdb will also now work within a PV guest without using the 'nokgdbroundup' workaround. Note that the 32-bit version is different and this patch does not enable that. CC: Lisa Nguyen <lisa@xenapiadmin.com> CC: Ben Guthro <benjamin.guthro@citrix.com> CC: Zhenzhong Duan <zhenzhong.duan@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [v1: Fixed up per David Vrabel comments] Reviewed-by: Ben Guthro <benjamin.guthro@citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com>
* | | Merge branch 'acpi-sleep'Rafael J. Wysocki2013-08-271-13/+28
|\ \ \ | |_|/ |/| | | | | | | | | | | | | | * acpi-sleep: x86 / tboot / ACPI: Fail extended mode reduced hardware sleep xen / ACPI: notify xen when reduced hardware sleep is available ACPI / sleep: Introduce acpi_os_prepare_extended_sleep() for extended sleep path
| * | xen / ACPI: notify xen when reduced hardware sleep is availableBen Guthro2013-07-311-13/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use the acpi_os_prepare_extended_sleep() callback to notify xen to make use of the reduced hardware sleep functionality The xen hypervisor change underlying this is commit 62d1a69 ("ACPI: support v5 (reduced HW) sleep interface") on the master branch of git://xenbits.xen.org/xen.git. Signed-off-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Ben Guthro <benjamin.guthro@citrix.com> Acked-by: Konrad Wilk <konrad.wilk@oracle.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | | Merge tag 'stable/for-linus-3.11-rc6-tag' of ↵Linus Torvalds2013-08-211-1/+12
|\ \ \ | |_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull Xen bug-fixes from Konrad Rzeszutek Wilk: - On ARM did not have balanced calls to get/put_cpu. - Fix to make tboot + Xen + Linux correctly. - Fix events VCPU binding issues. - Fix a vCPU online race where IPIs are sent to not-yet-online vCPU. * tag 'stable/for-linus-3.11-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/smp: initialize IPI vectors before marking CPU online xen/events: mask events when changing their VCPU binding xen/events: initialize local per-cpu mask for all possible events x86/xen: do not identity map UNUSABLE regions in the machine E820 xen/arm: missing put_cpu in xen_percpu_init
| * | xen/events: mask events when changing their VCPU bindingDavid Vrabel2013-08-201-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a event is being bound to a VCPU there is a window between the EVTCHNOP_bind_vpcu call and the adjustment of the local per-cpu masks where an event may be lost. The hypervisor upcalls the new VCPU but the kernel thinks that event is still bound to the old VCPU and ignores it. There is even a problem when the event is being bound to the same VCPU as there is a small window beween the clear_bit() and set_bit() calls in bind_evtchn_to_cpu(). When scanning for pending events, the kernel may read the bit when it is momentarily clear and ignore the event. Avoid this by masking the event during the whole bind operation. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> CC: stable@vger.kernel.org
| * | xen/events: initialize local per-cpu mask for all possible eventsDavid Vrabel2013-08-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The sizeof() argument in init_evtchn_cpu_bindings() is incorrect resulting in only the first 64 (or 32 in 32-bit guests) ports having their bindings being initialized to VCPU 0. In most cases this does not cause a problem as request_irq() will set the irq affinity which will set the correct local per-cpu mask. However, if the request_irq() is called on a VCPU other than 0, there is a window between the unmasking of the event and the affinity being set were an event may be lost because it is not locally unmasked on any VCPU. If request_irq() is called on VCPU 0 then local irqs are disabled during the window and the race does not occur. Fix this by initializing all NR_EVENT_CHANNEL bits in the local per-cpu masks. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> CC: stable@vger.kernel.org
* | | Merge tag 'stable/for-linus-3.11-rc3-tag' of ↵Linus Torvalds2013-07-314-26/+21
|\ \ \ | |/ / | | / | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull Xen fixes from Konrad Rzeszutek Wilk: - Three fixes for ARM/ARM64 to either compile or not certain generic drivers - Fix for avoiding a potential deadlock when an user space event channel is destroyed. - Fix a workqueue resuming multiple times. * tag 'stable/for-linus-3.11-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/tmem: do not allow XEN_TMEM on ARM64 xen/evtchn: avoid a deadlock when unbinding an event channel xen/arm: enable PV control for ARM xen/arm64: Don't compile cpu hotplug xenbus: frontend resume cleanup
| * xen/tmem: do not allow XEN_TMEM on ARM64Stefano Stabellini2013-07-301-1/+1
| | | | | | | | | | | | | | | | tmem is not supported on arm or arm64 yet. Will revert this once the Xen hypervisor supports it. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * xen/evtchn: avoid a deadlock when unbinding an event channelDavid Vrabel2013-07-301-19/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Unbinding an event channel (either with the ioctl or when the evtchn device is closed) may deadlock because disable_irq() is called with port_user_lock held which is also locked by the interrupt handler. Think of the IOCTL_EVTCHN_UNBIND is being serviced, the routine has just taken the lock, and an interrupt happens. The evtchn_interrupt is invoked, tries to take the lock and spins forever. A quick glance at the code shows that the spinlock is a local IRQ variant. Unfortunately that does not help as "disable_irq() waits for the interrupt handler on all CPUs to stop running. If the irq occurs on another VCPU, it tries to take port_user_lock and can't because the unbind ioctl is holding it." (from David). Hence we cannot depend on the said spinlock to protect us. We could make it a system wide IRQ disable spinlock but there is a better way. We can piggyback on the fact that the existence of the spinlock is to make get_port_user() checks be up-to-date. And we can alter those checks to not depend on the spin lock (as it's protected by u->bind_mutex in the ioctl) and can remove the unnecessary locking (this is IOCTL_EVTCHN_UNBIND) path. In the interrupt handler we cannot use the mutex, but we do not need it. "The unbind disables the irq before making the port user stale, so when you clear it you are guaranteed that the interrupt handler that might use that port cannot be running." (from David). Hence this patch removes the spinlock usage on the teardown path and piggybacks on disable_irq happening before we muck with the get_port_user() data. This ensures that the interrupt handler will never run on stale data. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [v1: Expanded the commit description a bit]
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