- 18 Dec, 2015 4 commits
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Roger Pau Monné authored
A compiler may load a switch statement value multiple times, which could be bad when the value is in memory shared with the frontend. When converting a non-native request to a native one, ensure that src->operation is only loaded once by using READ_ONCE(). This is part of XSA155. CC: stable@vger.kernel.org Signed-off-by:
Roger Pau Monné <roger.pau@citrix.com> Signed-off-by:
David Vrabel <david.vrabel@citrix.com> Signed-off-by:
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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David Vrabel authored
Instead of open-coding memcpy()s and directly accessing Tx and Rx requests, use the new RING_COPY_REQUEST() that ensures the local copy is correct. This is more than is strictly necessary for guest Rx requests since only the id and gref fields are used and it is harmless if the frontend modifies these. This is part of XSA155. CC: stable@vger.kernel.org Reviewed-by:
Wei Liu <wei.liu2@citrix.com> Signed-off-by:
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David Vrabel authored
The last from guest transmitted request gives no indication about the minimum amount of credit that the guest might need to send a packet since the last packet might have been a small one. Instead allow for the worst case 128 KiB packet. This is part of XSA155. CC: stable@vger.kernel.org Reviewed-by:
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David Vrabel authored
Using RING_GET_REQUEST() on a shared ring is easy to use incorrectly (i.e., by not considering that the other end may alter the data in the shared ring while it is being inspected). Safe usage of a request generally requires taking a local copy. Provide a RING_COPY_REQUEST() macro to use instead of RING_GET_REQUEST() and an open-coded memcpy(). This takes care of ensuring that the copy is done correctly regardless of any possible compiler optimizations. Use a volatile source to prevent the compiler from reordering or omitting the copy. This is part of XSA155. CC: stable@vger.kernel.org Signed-off-by:
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- 14 Dec, 2015 1 commit
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Boris Ostrovsky authored
Using MMUEXT_TLB_FLUSH_MULTI doesn't buy us much since the hypervisor will likely perform same IPIs as would have the guest. More importantly, using MMUEXT_INVLPG_MULTI may not to invalidate the guest's address on remote CPU (when, for example, VCPU from another guest is running there). Signed-off-by:
Boris Ostrovsky <boris.ostrovsky@oracle.com> Suggested-by:
Jan Beulich <jbeulich@suse.com> Signed-off-by:
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- 02 Dec, 2015 2 commits
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Boris Ostrovsky authored
Resuming PMU currently triggers a warning from ___might_sleep() (assuming CONFIG_DEBUG_ATOMIC_SLEEP is set) when xen_pmu_init() allocates GFP_KERNEL page because we are in state resembling atomic context. Move resuming PMU to xen_arch_resume() which is called in regular context. For symmetry move suspending PMU to xen_arch_suspend() as well. Signed-off-by:
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Ross Lagerwall authored
When a CPU is offlined, there may be unprocessed events on a port for that CPU. If the port is subsequently reused on a different CPU, it could be in an unexpected state with the link bit set, resulting in interrupts being missed. Fix this by consuming any unprocessed events for a particular CPU when that CPU dies. Signed-off-by:
Ross Lagerwall <ross.lagerwall@citrix.com> Cc: <stable@vger.kernel.org> # 3.14+ Signed-off-by:
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- 26 Nov, 2015 3 commits
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David Vrabel authored
If more than 1024 event channels are bound to a evtchn device then it possible (even with well behaved applications) for the ring to overflow and events to be lost (reported as an -EFBIG error). Dynamically increase the size of the ring so there is always enough space for all bound events. Well behaved applicables that only unmask events after draining them from the ring can thus no longer lose events. However, an application could unmask an event before draining it, allowing multiple entries per port to accumulate in the ring, and a overflow could still occur. So the overflow detection and reporting is retained. The ring size is initially only 64 entries so the common use case of an application only binding a few events will use less memory than before. The ring size may grow to 512 KiB (enough for all 2^17 possible channels). This order 7 kmalloc() may fail due to memory fragmentation, so we fall back to trying vmalloc(). Signed-off-by:
Andrew Cooper <andrew.cooper3@citrix.com>
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Boris Ostrovsky authored
After commit 8c058b0b ("x86/irq: Probe for PIC presence before allocating descs for legacy IRQs") early_irq_init() will no longer preallocate descriptors for legacy interrupts if PIC does not exist, which is the case for Xen PV guests. Therefore we may need to allocate those descriptors ourselves. Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
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Boris Ostrovsky authored
Doing so will cause the grant to be unmapped and then, during fault handling, the fault to be mistakenly treated as NUMA hint fault. In addition, even if those maps could partcipate in NUMA balancing, it wouldn't provide any benefit since we are unable to determine physical page's node (even if/when VNUMA is implemented). Marking grant maps' VMAs as VM_IO will exclude them from being part of NUMA balancing. Signed-off-by:
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- 02 Nov, 2015 1 commit
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Zhenzhong Duan authored
On some NUMA system, after dom0 up, we see below warning even if there are enough pfn ranges that could be used for remapping: "Unable to find available pfn range, not remapping identity pages" Fix it to avoid getting a memory region of zero size in xen_find_pfn_range. Signed-off-by:
Zhenzhong Duan <zhenzhong.duan@oracle.com> Reviewed-by:
Juergen Gross <jgross@suse.com> Signed-off-by:
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- 28 Oct, 2015 1 commit
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David Vrabel authored
Mapping a large range of foreign GFNs can take a long time, add a reschedule point after each batch of 16 GFNs. Signed-off-by:
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- 23 Oct, 2015 28 commits
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Stefano Stabellini authored
Call disable_percpu_irq on CPU_DYING and enable_percpu_irq when the cpu is coming up. Signed-off-by:
Stefano Stabellini <stefano.stabellini@eu.citrix.com> Reviewed-by:
Julien Grall <julien.grall@citrix.com>
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Stefano Stabellini authored
When offlining a cpu, instead of cpu_down, call device_offline, which also takes care of updating the cpu.dev.offline field. This keeps the sysfs file /sys/devices/system/cpu/cpuN/online, up to date. Also move the call to disable_hotplug_cpu, because it makes more sense to have it there. We don't call device_online at cpu-hotplug time, because that would immediately take the cpu online, while we want to retain the current behaviour: the user needs to explicitly enable the cpu after it has been hotplugged. Signed-off-by:
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Stefano Stabellini authored
Build cpu_hotplug for ARM and ARM64 guests. Rename arch_(un)register_cpu to xen_(un)register_cpu and provide an empty implementation on ARM and ARM64. On x86 just call arch_(un)register_cpu as we are already doing. Initialize cpu_hotplug on ARM. Signed-off-by:
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Julien Grall authored
The PV ring may use multiple grants and expect them to be mapped contiguously in the virtual memory. Although, the current code is relying on a Linux page will be mapped to a single grant. On build where Linux is using a different page size than the grant (i.e other than 4KB), the grant will always be mapped on the first 4KB of each Linux page which make the final ring not contiguous in the memory. This can be fixed by mapping multiple grant in a same Linux page. Signed-off-by:
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Julien Grall authored
With the 64KB page granularity support on ARM64, a Linux page may be split accross multiple grant. Currently we have the helper gnttab_foreach_grant_in_grant to break a Linux page based on an offset and a len, but it doesn't fit when we only have a number of grants in hand. Introduce a new helper which take an array of Linux page and a number of grant and will figure out the address of each grant. Signed-off-by:
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Julien Grall authored
Linux may use a different page size than the size of grant. So make clear that the order is actually in number of grant. Signed-off-by:
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Juergen Gross authored
Correct a comment in arch/arm/xen/enlighten.c referencing a wrong source file. Signed-off-by:
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Mikko Rapeli authored
__u32, __u64 etc. are preferred for userspace API headers. Signed-off-by:
Mikko Rapeli <mikko.rapeli@iki.fi> Signed-off-by:
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Mikko Rapeli authored
__u32, __u64 etc. are preferred for userspace API headers. Signed-off-by:
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Julien Grall authored
The type of the item in frame_list is xen_pfn_t which is not an unsigned long on ARM but an uint64_t. With the current computation, the size of frame_list will be 2 * PAGE_SIZE rather than PAGE_SIZE. I bet it's just mistake when the type has been switched from "unsigned long" to "xen_pfn_t" in commit 965c0aaa "xen: balloon: use correct type for frame_list". Signed-off-by:
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Julien Grall authored
Swiotlb is used on ARM64 to support DMA on platform where devices are not protected by an SMMU. Furthermore it's only enabled for DOM0. While Xen is always using 4KB page granularity in the stage-2 page table, Linux ARM64 may either use 4KB or 64KB. This means that a Linux page can be spanned accross multiple Xen page. The Swiotlb code has to validate that the buffer used for DMA is physically contiguous in the memory. As a Linux page can't be shared between local memory and foreign page by design (the balloon code always removing entirely a Linux page), the changes in the code are very minimal because we only need to check the first Xen PFN. Note that it may be possible to optimize the function check_page_physically_contiguous to avoid looping over every Xen PFN for local memory. Although I will let this optimization for a follow-up. Signed-off-by:
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Julien Grall authored
With 64KB page granularity support, the frame number will be different. It will be easier to modify the behavior in a single place rather than in each caller. Signed-off-by:
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Julien Grall authored
The hypercall interface is always using 4KB page granularity. This is requiring to use xen page definition macro when we deal with hypercall. Note that pfn_to_gfn is working with a Xen pfn (i.e 4KB). We may want to rename pfn_gfn to make this explicit. We also allocate a 64KB page for the shared page even though only the first 4KB is used. I don't think this is really important for now as it helps to have the pointer 4KB aligned (XENMEM_add_to_physmap is taking a Xen PFN). Signed-off-by:
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Julien Grall authored
The hypercall interface (as well as the toolstack) is always using 4KB page granularity. When the toolstack is asking for mapping a series of guest PFN in a batch, it expects to have the page map contiguously in its virtual memory. When Linux is using 64KB page granularity, the privcmd driver will have to map multiple Xen PFN in a single Linux page. Note that this solution works on page granularity which is a multiple of 4KB. Signed-off-by:
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Julien Grall authored
The PV network protocol is using 4KB page granularity. The goal of this patch is to allow a Linux using 64KB page granularity working as a network backend on a non-modified Xen. It's only necessary to adapt the ring size and break skb data in small chunk of 4KB. The rest of the code is relying on the grant table code. Signed-off-by:
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Julien Grall authored
The PV network protocol is using 4KB page granularity. The goal of this patch is to allow a Linux using 64KB page granularity using network device on a non-modified Xen. It's only necessary to adapt the ring size and break skb data in small chunk of 4KB. The rest of the code is relying on the grant table code. Note that we allocate a Linux page for each rx skb but only the first 4KB is used. We may improve the memory usage by extending the size of the rx skb. Signed-off-by:
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Julien Grall authored
The PV block protocol is using 4KB page granularity. The goal of this patch is to allow a Linux using 64KB page granularity behaving as a block backend on a non-modified Xen. It's only necessary to adapt the ring size and the number of request per indirect frames. The rest of the code is relying on the grant table code. Note that the grant table code is allocating a Linux page per grant which will result to waste 6OKB for every grant when Linux is using 64KB page granularity. This could be improved by sharing the page between multiple grants. Signed-off-by:
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Julien Grall authored
The PV block protocol is using 4KB page granularity. The goal of this patch is to allow a Linux using 64KB page granularity using block device on a non-modified Xen. The block API is using segment which should at least be the size of a Linux page. Therefore, the driver will have to break the page in chunk of 4K before giving the page to the backend. When breaking a 64KB segment in 4KB chunks, it is possible that some chunks are empty. As the PV protocol always require to have data in the chunk, we have to count the number of Xen page which will be in use and avoid sending empty chunks. Note that, a pre-defined number of grants are reserved before preparing the request. This pre-defined number is based on the number and the maximum size of the segments. If each segment contains a very small amount of data, the driver may reserve too many grants (16 grants is reserved per segment with 64KB page granularity). Furthermore, in the case of persistent grants we allocate one Linux page per grant although only the first 4KB of the page will be effectively in use. This could be improved by sharing the page with multiple grants. Signed-off-by:
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Julien Grall authored
The Xen interface is using 4KB page granularity. This means that each grant is 4KB. The current implementation allocates a Linux page per grant. On Linux using 64KB page granularity, only the first 4KB of the page will be used. We could decrease the memory wasted by sharing the page with multiple grant. It will require some care with the {Set,Clear}ForeignPage macro. Note that no changes has been made in the x86 code because both Linux and Xen will only use 4KB page granularity. Signed-off-by: -
Julien Grall authored
Only use the first 4KB of the page to store the events channel info. It means that we will waste 60KB every time we allocate page for: * control block: a page is allocating per CPU * event array: a page is allocating everytime we need to expand it I think we can reduce the memory waste for the 2 areas by: * control block: sharing between multiple vCPUs. Although it will require some bookkeeping in order to not free the page when the CPU goes offline and the other CPUs sharing the page still there * event array: always extend the array event by 64K (i.e 16 4K chunk). That would require more care when we fail to expand the event channel. Signed-off-by:Stefano Stabellini <stefano.stabellini@citrix.com> Signed-off-by:
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Julien Grall authored
For ARM64 guests, Linux is able to support either 64K or 4K page granularity. Although, the hypercall interface is always based on 4K page granularity. With 64K page granularity, a single page will be spread over multiple Xen frame. To avoid splitting the page into 4K frame, take advantage of the extent_order field to directly allocate/free chunk of the Linux page size. Note that PVMMU is only used for PV guest (which is x86) and the page granularity is always 4KB. Some BUILD_BUG_ON has been added to ensure that because the code has not been modified. Signed-off-by:
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Julien Grall authored
The console ring is always based on the page granularity of Xen. Signed-off-by:
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Julien Grall authored
All the ring (xenstore, and PV rings) are always based on the page granularity of Xen. Signed-off-by:
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Julien Grall authored
On ARM all dma-capable devices on a same platform may not be protected by an IOMMU. The DMA requests have to use the BFN (i.e MFN on ARM) in order to use correctly the device. While the DOM0 memory is allocated in a 1:1 fashion (PFN == MFN), grant mapping will screw this contiguous mapping. When Linux is using 64KB page granularitary, the page may be split accross multiple non-contiguous MFN (Xen is using 4KB page granularity). Therefore a DMA request will likely fail. Checking that a 64KB page is using contiguous MFN is tedious. For now, always says that biovec are not mergeable. Signed-off-by:
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Julien Grall authored
Prepare the code to support 64KB page granularity. The first implementation will use a full Linux page per indirect and persistent grant. When non-persistent grant is used, each page of a bio request may be split in multiple grant. Furthermore, the field page of the grant structure is only used to copy data from persistent grant or indirect grant. Avoid to set it for other use case as it will have no meaning given the page will be split in multiple grant. Provide 2 functions, to setup indirect grant, the other for bio page. Signed-off-by:
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Julien Grall authored
All the usage of the field pfn are done using the same idiom: pfn_to_page(grant->pfn) This will return always the same page. Store directly the page in the grant to clean up the code. Signed-off-by:
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Julien Grall authored
Currently, blkif_queue_request has 2 distinct execution path: - Send a discard request - Send a read/write request The function is also allocating grants to use for generating the request. Although, this is only used for read/write request. Rather than having a function with 2 distinct execution path, separate the function in 2. This will also remove one level of tabulation. Signed-off-by: -
Julien Grall authored
Many PV drivers contain the idiom: pfn = page_to_gfn(...) /* Or similar */ gnttab_grant_foreign_access_ref Replace it by a new helper. Note that when Linux is using a different page granularity than Xen, the helper only gives access to the first 4KB grant. This is useful where drivers are allocating a full Linux page for each grant. Also include xen/interface/grant_table.h rather than xen/grant_table.h in asm/page.h for x86 to fix a compilation issue [1]. Only the former is useful in order to get the structure definition. [1] Interdependency between asm/page.h and xen/grant_table.h which result to page_mfn not being defined when necessary. Signed-off-by:
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