kernel.git/drivers/xen/grant-table.c, branch linux-3.19.y

xen/grant-table: refactor error cleanup in grow_gnttab_list()

2014-09-23T13:36:18Z

The cleanup loop in grow_gnttab_list() is safe from the underflow of the unsigned 'i' since nr_glist_frames is >= 1, but refactor it anyway. Signed-off-by: Chen Gang Signed-off-by: David Vrabel

xen/grant-table: remove support for V2 tables

2014-07-14T19:28:30Z

Since 11c7ff17c9b6dbf3a4e4f36be30ad531a6cf0ec9 (xen/grant-table: Force to use v1 of grants.) the code for V2 grant tables is not used. Signed-off-by: David Vrabel Signed-off-by: Konrad Rzeszutek Wilk

x86/xen: safely map and unmap grant frames when in atomic context

2014-07-14T19:28:02Z

arch_gnttab_map_frames() and arch_gnttab_unmap_frames() are called in atomic context but were calling alloc_vm_area() which might sleep. Also, if a driver attempts to allocate a grant ref from an interrupt and the table needs expanding, then the CPU may already by in lazy MMU mode and apply_to_page_range() will BUG when it tries to re-enable lazy MMU mode. These two functions are only used in PV guests. Introduce arch_gnttab_init() to allocates the virtual address space in advance. Avoid the use of apply_to_page_range() by using saving and using the array of PTE addresses from the alloc_vm_area() call. N.B. 'alloc_vm_area' pre-allocates the pagetable so there is no need to worry about having to do a PGD/PUD/PMD walk (like apply_to_page_range does) and we can instead do set_pte. Signed-off-by: David Vrabel Signed-off-by: Konrad Rzeszutek Wilk ---- [v2: Add comment about alloc_vm_area] [v3: Fix compile error found by 0-day bot]

xen/grant-table: fix suspend for non-PV guests

2014-06-18T09:58:01Z

Commit aa8532c32216ae07c3813b9aeb774517878a7573 (xen: refactor suspend pre/post hooks) broke resuming PVHVM (auto-translated physmap) guests. The gnttab_suspend() would clear the mapping for the grant table frames, but the ->unmap_frames() call is only applicable to PV guests. Signed-off-by: David Vrabel Reported-by: Konrad Rzeszutek Wilk Tested-by: Konrad Rzeszutek Wilk

xen/grant-table: Refactor gnttab_[un]map_refs to avoid m2p_override

2014-03-18T14:40:19Z

The grant mapping API does m2p_override unnecessarily: only gntdev needs it, for blkback and future netback patches it just cause a lock contention, as those pages never go to userspace. Therefore this series does the following: - the bulk of the original function (everything after the mapping hypercall) is moved to arch-dependent set/clear_foreign_p2m_mapping - the "if (xen_feature(XENFEAT_auto_translated_physmap))" branch goes to ARM - therefore the ARM function could be much smaller, the m2p_override stubs could be also removed - on x86 the set_phys_to_machine calls were moved up to this new funcion from m2p_override functions - and m2p_override functions are only called when there is a kmap_ops param It also removes a stray space from arch/x86/include/asm/xen/page.h. Signed-off-by: Zoltan Kiss Suggested-by: Anthony Liguori Suggested-by: David Vrabel Suggested-by: Stefano Stabellini Signed-off-by: David Vrabel Signed-off-by: Stefano Stabellini

Revert "xen/grant-table: Avoid m2p_override during mapping"

2014-02-03T11:44:49Z

This reverts commit 08ece5bb2312b4510b161a6ef6682f37f4eac8a1. As it breaks ARM builds and needs more attention on the ARM side. Acked-by: David Vrabel Signed-off-by: Konrad Rzeszutek Wilk

xen/grant-table: Avoid m2p_override during mapping

2014-01-31T14:48:32Z

The grant mapping API does m2p_override unnecessarily: only gntdev needs it, for blkback and future netback patches it just cause a lock contention, as those pages never go to userspace. Therefore this series does the following: - the original functions were renamed to __gnttab_[un]map_refs, with a new parameter m2p_override - based on m2p_override either they follow the original behaviour, or just set the private flag and call set_phys_to_machine - gnttab_[un]map_refs are now a wrapper to call __gnttab_[un]map_refs with m2p_override false - a new function gnttab_[un]map_refs_userspace provides the old behaviour It also removes a stray space from page.h and change ret to 0 if XENFEAT_auto_translated_physmap, as that is the only possible return value there. v2: - move the storing of the old mfn in page->index to gnttab_map_refs - move the function header update to a separate patch v3: - a new approach to retain old behaviour where it needed - squash the patches into one v4: - move out the common bits from m2p* functions, and pass pfn/mfn as parameter - clear page->private before doing anything with the page, so m2p_find_override won't race with this v5: - change return value handling in __gnttab_[un]map_refs - remove a stray space in page.h - add detail why ret = 0 now at some places v6: - don't pass pfn to m2p* functions, just get it locally Signed-off-by: Zoltan Kiss Suggested-by: David Vrabel Acked-by: David Vrabel Acked-by: Stefano Stabellini Signed-off-by: Konrad Rzeszutek Wilk

xen/gnttab: Use phys_addr_t to describe the grant frame base address

2014-01-30T12:56:34Z

On ARM, address size can be 32 bits or 64 bits (if CONFIG_ARCH_PHYS_ADDR_T_64BIT is enabled). We can't assume that the grant frame base address will always fits in an unsigned long. Use phys_addr_t instead of unsigned long as argument for gnttab_setup_auto_xlat_frames. Signed-off-by: Julien Grall Signed-off-by: Stefano Stabellini Acked-by: Ian Campbell Reviewed-by: David Vrabel

xen/grant-table: Force to use v1 of grants.

2014-01-06T15:44:39Z

We have the framework to use v2, but there are no backends that actually use it. The end result is that on PV we use v2 grants and on PVHVM v1. The v1 has a capacity of 512 grants per page while the v2 has 256 grants per page. This means we lose about 50% capacity - and if we want more than 16 VIFs (each VIF takes 512 grants), then we are hitting the max per guest of 32. Oracle-bug: 16039922 CC: annie.li@oracle.com CC: msw@amazon.com Signed-off-by: Konrad Rzeszutek Wilk Reviewed-by: David Vrabel

xen/pvh: Piggyback on PVHVM for grant driver (v4)

2014-01-06T15:44:21Z

In PVH the shared grant frame is the PFN and not MFN, hence its mapped via the same code path as HVM. The allocation of the grant frame is done differently - we do not use the early platform-pci driver and have an ioremap area - instead we use balloon memory and stitch all of the non-contingous pages in a virtualized area. That means when we call the hypervisor to replace the GMFN with a XENMAPSPACE_grant_table type, we need to lookup the old PFN for every iteration instead of assuming a flat contingous PFN allocation. Lastly, we only use v1 for grants. This is because PVHVM is not able to use v2 due to no XENMEM_add_to_physmap calls on the error status page (see commit 69e8f430e243d657c2053f097efebc2e2cd559f0 xen/granttable: Disable grant v2 for HVM domains.) Until that is implemented this workaround has to be in place. Also per suggestions by Stefano utilize the PVHVM paths as they share common functionality. v2 of this patch moves most of the PVH code out in the arch/x86/xen/grant-table driver and touches only minimally the generic driver. v3, v4: fixes us some of the code due to earlier patches. Signed-off-by: Konrad Rzeszutek Wilk Acked-by: Stefano Stabellini