kernel.git/drivers/xen/balloon.c, branch linux-4.3.y

xen: Use correctly the Xen memory terminologies

2015-09-08T17:03:49Z

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 Reviewed-by: Stefano Stabellini Acked-by: Dmitry Torokhov Acked-by: Wei Liu Signed-off-by: David Vrabel

xen: switch extra memory accounting to use pfns

2015-09-08T15:28:06Z

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 Tested-by: Roger Pau Monné Signed-off-by: Juergen Gross Signed-off-by: David Vrabel

xen: release lock occasionally during ballooning

2015-07-20T12:37:05Z

When dom0 is being ballooned balloon_process() will hold the balloon mutex until it is finished. This will block e.g. creation of new domains as the device backends for the new domain need some autoballooned pages for the ring buffers. Avoid this by releasing the balloon mutex from time to time during ballooning. Adjust the comment above balloon_process() regarding multiple instances of balloon_process(). Instead of open coding it, just use cond_resched(). Signed-off-by: Juergen Gross Signed-off-by: David Vrabel

xen/balloon: before adding hotplugged memory, set frames to invalid

2015-03-23T15:15:53Z

Commit 25b884a83d487fd62c3de7ac1ab5549979188482 ("x86/xen: set regions above the end of RAM as 1:1") introduced a regression. To be able to add memory pages which were added via memory hotplug to a pv domain, the pages must be "invalid" instead of "identity" in the p2m list before they can be added. Suggested-by: David Vrabel Signed-off-by: Juergen Gross Cc: # 3.16+ Reviewed-by: Daniel Kiper Signed-off-by: David Vrabel

xen: remove scratch frames for ballooned pages and m2p override

2015-01-28T14:03:10Z

The scratch frame mappings for ballooned pages and the m2p override are broken. Remove them in preparation for replacing them with simpler mechanisms that works. The scratch pages did not ensure that the page was not in use. In particular, the foreign page could still be in use by hardware. If the guest reused the frame the hardware could read or write that frame. The m2p override did not handle the same frame being granted by two different grant references. Trying an M2P override lookup in this case is impossible. With the m2p override removed, the grant map/unmap for the kernel mappings (for x86 PV) can be easily batched in set_foreign_p2m_mapping() and clear_foreign_p2m_mapping(). Signed-off-by: David Vrabel Reviewed-by: Stefano Stabellini

xen/balloon: Don't continue ballooning when BP_ECANCELED is encountered

2014-10-23T15:24:01Z

Commit 3dcf63677d4e ("xen/balloon: cancel ballooning if adding new memory failed") makes reserve_additional_memory() return BP_ECANCELED when an error is encountered. This error, however, is ignored by the caller (balloon_process()) since it is overwritten by subsequent call to update_schedule(). This results in continuous attempts to add more memory, all of which are likely to fail again. We should stop trying to schedule next iteration of ballooning when the current one has failed. Signed-off-by: Boris Ostrovsky Reviewed-by: Daniel Kiper Signed-off-by: David Vrabel

xen/balloon: cancel ballooning if adding new memory failed

2014-09-02T14:37:19Z

If the balloon driver is adding additional memory regions to the balloon and add_memory() fails it will likely continuously fail so cancel the balloon operation. Signed-off-by: David Vrabel Reviewed-by: Daniel Kiper

xen/balloon: set ballooned out pages as invalid in p2m

2014-07-04T14:17:43Z

Since cd9151e26d31048b2b5e00fd02e110e07d2200c9 (xen/balloon: set a mapping for ballooned out pages), a ballooned out page had its entry in the p2m set to the MFN of one of the scratch pages. This means that the p2m will contain many entries pointing to the same MFN. During a domain save, these many-to-one entries are not identified as such and the scratch page is saved multiple times. On restore the ballooned pages are populated with new frames and the domain may use up its allocation before all pages can be restored. Since the original fix only needed to keep a mapping for the ballooned page it is safe to set ballooned out pages as INVALID_P2M_ENTRY in the p2m (as they were before). Thus preventing them from being saved and re-populated on restore. Signed-off-by: David Vrabel Reported-by: Marek Marczykowski Tested-by: Marek Marczykowski Acked-by: Stefano Stabellini Cc:

Merge tag 'cpu-hotplug-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2014-04-07T21:55:46Z

Pull CPU hotplug notifiers registration fixes from Rafael Wysocki: "The purpose of this single series of commits from Srivatsa S Bhat (with a small piece from Gautham R Shenoy) touching multiple subsystems that use CPU hotplug notifiers is to provide a way to register them that will not lead to deadlocks with CPU online/offline operations as described in the changelog of commit 93ae4f978ca7f ("CPU hotplug: Provide lockless versions of callback registration functions"). The first three commits in the series introduce the API and document it and the rest simply goes through the users of CPU hotplug notifiers and converts them to using the new method" * tag 'cpu-hotplug-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (52 commits) net/iucv/iucv.c: Fix CPU hotplug callback registration net/core/flow.c: Fix CPU hotplug callback registration mm, zswap: Fix CPU hotplug callback registration mm, vmstat: Fix CPU hotplug callback registration profile: Fix CPU hotplug callback registration trace, ring-buffer: Fix CPU hotplug callback registration xen, balloon: Fix CPU hotplug callback registration hwmon, via-cputemp: Fix CPU hotplug callback registration hwmon, coretemp: Fix CPU hotplug callback registration thermal, x86-pkg-temp: Fix CPU hotplug callback registration octeon, watchdog: Fix CPU hotplug callback registration oprofile, nmi-timer: Fix CPU hotplug callback registration intel-idle: Fix CPU hotplug callback registration clocksource, dummy-timer: Fix CPU hotplug callback registration drivers/base/topology.c: Fix CPU hotplug callback registration acpi-cpufreq: Fix CPU hotplug callback registration zsmalloc: Fix CPU hotplug callback registration scsi, fcoe: Fix CPU hotplug callback registration scsi, bnx2fc: Fix CPU hotplug callback registration scsi, bnx2i: Fix CPU hotplug callback registration ...

xen/balloon: flush persistent kmaps in correct position

2014-03-25T10:38:30Z

Xen balloon driver will update ballooned out pages' P2M entries to point to scratch page for PV guests. In 24f69373e2 ("xen/balloon: don't alloc page while non-preemptible", kmap_flush_unused was moved after updating P2M table. In that case for 32 bit PV guest we might end up with P2M X -----> S (S is mfn of balloon scratch page) M2P Y -----> X (Y is mfn in persistent kmap entry) kmap_flush_unused() iterates through all the PTEs in the kmap address space, using pte_to_page() to obtain the page. If the p2m and the m2p are inconsistent the incorrect page is returned. This will clear page->address on the wrong page which may cause subsequent oopses if that page is currently kmap'ed. Move the flush back between get_page and __set_phys_to_machine to fix this. Signed-off-by: Wei Liu Signed-off-by: David Vrabel Cc: stable@vger.kernel.org # 3.12+