xen: Fix page <-> pfn conversion on 32 bit systems commit 60901df3aed230d4565dca003f11b6a95fbf30d9 upstream. Commit 1084b1988d22dc165c9dbbc2b0e057f9248ac4db (xen: Add Xen specific page definition) caused a regression in 4.4. The xen functions to convert between pages and pfns fail due to an overflow on systems where a physical address may not fit in an unsigned long (e.g. x86 32 bit PAE systems). Rework the conversion to avoid overflow. This should also result in simpler object code. This bug manifested itself as disk corruption with Linux 4.4 when using blkfront in a Xen HVM x86 32 bit guest with more than 4 GiB of memory. Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
xen: Add RING_COPY_REQUEST() 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: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen/grant-table: Add an helper to iterate over a specific number of grants 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: Julien Grall <julien.grall@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
xen/xenbus: Rename *RING_PAGE* to *RING_GRANT* 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: Julien Grall <julien.grall@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
xen/grant: Add helper gnttab_page_grant_foreign_access_ref_one 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: Julien Grall <julien.grall@citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
xen/grant: Introduce helpers to split a page into grant Currently, a grant is always based on the Xen page granularity (i.e 4KB). When Linux is using a different page granularity, a single page will be split between multiple grants. The new helpers will be in charge of splitting the Linux page into grants and call a function given by the caller on each grant. Also provide an helper to count the number of grants within a given contiguous region. Note that the x86/include/asm/xen/page.h is now including xen/interface/grant_table.h rather than xen/grant_table.h. It's necessary because xen/grant_table.h depends on asm/xen/page.h and will break the compilation. Furthermore, only definition in interface/grant_table.h is required. Signed-off-by: Julien Grall <julien.grall@citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
xen: Add Xen specific page definition The Xen hypercall interface is always using 4K page granularity on ARM and x86 architecture. With the incoming support of 64K page granularity for ARM64 guest, it won't be possible to re-use the Linux page definition in Xen drivers. Introduce Xen page definition helpers based on the Linux page definition. They have exactly the same name but prefixed with XEN_/xen_ prefix. Also modify xen_page_to_gfn to use new Xen page definition. Signed-off-by: Julien Grall <julien.grall@citrix.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
xen/balloon: use hotplugged pages for foreign mappings etc. alloc_xenballooned_pages() is used to get ballooned pages to back foreign mappings etc. Instead of having to balloon out real pages, use (if supported) hotplugged memory. This makes more memory available to the guest and reduces fragmentation in the p2m. This is only enabled if the xen.balloon.hotplug_unpopulated sysctl is set to 1. This sysctl defaults to 0 in case the udev rules to automatically online hotplugged memory do not exist. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> --- v3: - Add xen.balloon.hotplug_unpopulated sysctl to enable use of hotplug for unpopulated pages.
xen/balloon: make alloc_xenballoon_pages() always allocate low pages All users of alloc_xenballoon_pages() wanted low memory pages, so remove the option for high memory. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
xen/balloon: rationalize memory hotplug stats The stats used for memory hotplug make no sense and are fiddled with in odd ways. Remove them and introduce total_pages to track the total number of pages (both populated and unpopulated) including those within hotplugged regions (note that this includes not yet onlined pages). This will be used in a subsequent commit (xen/balloon: only hotplug additional memory if required) when deciding whether additional memory needs to be hotplugged. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
xen/balloon: remove scratch page left overs Commit 0bb599fd30108883b00c7d4a226eeb49111e6932 (xen: remove scratch frames for ballooned pages and m2p override) removed the use of the scratch page for ballooned out pages. Remove some left over function definitions. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
x86/xen: Support kexec/kdump in HVM guests by doing a soft reset Currently there is a number of issues preventing PVHVM Xen guests from doing successful kexec/kdump: - Bound event channels. - Registered vcpu_info. - PIRQ/emuirq mappings. - shared_info frame after XENMAPSPACE_shared_info operation. - Active grant mappings. Basically, newly booted kernel stumbles upon already set up Xen interfaces and there is no way to reestablish them. In Xen-4.7 a new feature called 'soft reset' is coming. A guest performing kexec/kdump operation is supposed to call SCHEDOP_shutdown hypercall with SHUTDOWN_soft_reset reason before jumping to new kernel. Hypervisor (with some help from toolstack) will do full domain cleanup (but keeping its memory and vCPU contexts intact) returning the guest to the state it had when it was first booted and thus allowing it to start over. Doing SHUTDOWN_soft_reset on Xen hypervisors which don't support it is probably OK as by default all unknown shutdown reasons cause domain destroy with a message in toolstack log: 'Unknown shutdown reason code 5. Destroying domain.' which gives a clue to what the problem is and eliminates false expectations. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Merge tag 'for-linus-4.3-rc0b-tag' of git://git./linux/kernel/git/xen/tip Pull xen terminology fixes from David Vrabel: "Use the correct GFN/BFN terms more consistently" * tag 'for-linus-4.3-rc0b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/xenbus: Rename the variable xen_store_mfn to xen_store_gfn xen/privcmd: Further s/MFN/GFN/ clean-up hvc/xen: Further s/MFN/GFN clean-up video/xen-fbfront: Further s/MFN/GFN clean-up xen/tmem: Use xen_page_to_gfn rather than pfn_to_gfn xen: Use correctly the Xen memory terminologies arm/xen: implement correctly pfn_to_mfn xen: Make clear that swiotlb and biomerge are dealing with DMA address
Merge tag 'for-linus-4.3-rc0-tag' of git://git./linux/kernel/git/xen/tip Pull xen updates from David Vrabel: "Xen features and fixes for 4.3: - Convert xen-blkfront to the multiqueue API - [arm] Support binding event channels to different VCPUs. - [x86] Support > 512 GiB in a PV guests (off by default as such a guest cannot be migrated with the current toolstack). - [x86] PMU support for PV dom0 (limited support for using perf with Xen and other guests)" * tag 'for-linus-4.3-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (33 commits) xen: switch extra memory accounting to use pfns xen: limit memory to architectural maximum xen: avoid another early crash of memory limited dom0 xen: avoid early crash of memory limited dom0 arm/xen: Remove helpers which are PV specific xen/x86: Don't try to set PCE bit in CR4 xen/PMU: PMU emulation code xen/PMU: Intercept PMU-related MSR and APIC accesses xen/PMU: Describe vendor-specific PMU registers xen/PMU: Initialization code for Xen PMU xen/PMU: Sysfs interface for setting Xen PMU mode xen: xensyms support xen: remove no longer needed p2m.h xen: allow more than 512 GB of RAM for 64 bit pv-domains xen: move p2m list if conflicting with e820 map xen: add explicit memblock_reserve() calls for special pages mm: provide early_memremap_ro to establish read-only mapping xen: check for initrd conflicting with e820 map xen: check pre-allocated page tables for conflict with memory map xen: check for kernel memory conflicting with memory layout ...
xen/privcmd: Further s/MFN/GFN/ clean-up The privcmd code is mixing the usage of GFN and MFN within the same functions which make the code difficult to understand when you only work with auto-translated guests. The privcmd driver is only dealing with GFN so replace all the mention of MFN into GFN. The ioctl structure used to map foreign change has been left unchanged given that the userspace is using it. Nonetheless, add a comment to explain the expected value within the "mfn" field. Signed-off-by: Julien Grall <julien.grall@citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
xen: Use correctly the Xen memory terminologies Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN is meant, I suspect this is because the first support for Xen was for PV. This resulted in some misimplementation of helpers on ARM and confused developers about the expected behavior. For instance, with pfn_to_mfn, we expect to get an MFN based on the name. Although, if we look at the implementation on x86, it's returning a GFN. For clarity and avoid new confusion, replace any reference to mfn with gfn in any helpers used by PV drivers. The x86 code will still keep some reference of pfn_to_mfn which may be used by all kind of guests No changes as been made in the hypercall field, even though they may be invalid, in order to keep the same as the defintion in xen repo. Note that page_to_mfn has been renamed to xen_page_to_gfn to avoid a name to close to the KVM function gfn_to_page. Take also the opportunity to simplify simple construction such as pfn_to_mfn(page_to_pfn(page)) into xen_page_to_gfn. More complex clean up will come in follow-up patches. [1] http://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=e758ed14f390342513405dd766e874934573e6cb Signed-off-by: Julien Grall <julien.grall@citrix.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Acked-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
xen: switch extra memory accounting to use pfns Instead of using physical addresses for accounting of extra memory areas available for ballooning switch to pfns as this is much less error prone regarding partial pages. Reported-by: Roger Pau Monné <roger.pau@citrix.com> Tested-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
xen-netback: add support for multicast control Xen's PV network protocol includes messages to add/remove ethernet multicast addresses to/from a filter list in the backend. This allows the frontend to request the backend only forward multicast packets which are of interest thus preventing unnecessary noise on the shared ring. The canonical netif header in git://xenbits.xen.org/xen.git specifies the message format (two more XEN_NETIF_EXTRA_TYPEs) so the minimal necessary changes have been pulled into include/xen/interface/io/netif.h. To prevent the frontend from extending the multicast filter list arbitrarily a limit (XEN_NETBK_MCAST_MAX) has been set to 64 entries. This limit is not specified by the protocol and so may change in future. If the limit is reached then the next XEN_NETIF_EXTRA_TYPE_MCAST_ADD sent by the frontend will be failed with NETIF_RSP_ERROR. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Acked-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
xen/PMU: Intercept PMU-related MSR and APIC accesses Provide interfaces for recognizing accesses to PMU-related MSRs and LVTPC APIC and process these accesses in Xen PMU code. (The interrupt handler performs XENPMU_flush right away in the beginning since no PMU emulation is available. It will be added with a later patch). Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
xen/PMU: Initialization code for Xen PMU Map shared data structure that will hold CPU registers, VPMU context, V/PCPU IDs of the CPU interrupted by PMU interrupt. Hypervisor fills this information in its handler and passes it to the guest for further processing. Set up PMU VIRQ. Now that perf infrastructure will assume that PMU is available on a PV guest we need to be careful and make sure that accesses via RDPMC instruction don't cause fatal traps by the hypervisor. Provide a nop RDPMC handler. For the same reason avoid issuing a warning on a write to APIC's LVTPC. Both of these will be made functional in later patches. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>