kernel/include/xen/xen-ops.h, branch linux-5.11.y

x86/entry: Switch XEN/PV hypercall entry to IDTENTRY

2020-06-11T13:15:08Z

Convert the XEN/PV hypercall to IDTENTRY: - Emit the ASM stub with DECLARE_IDTENTRY - Remove the ASM idtentry in 64-bit - Remove the open coded ASM entry code in 32-bit - Remove the old prototypes The handler stubs need to stay in ASM code as they need corner case handling and adjustment of the stack pointer. Provide a new C function which invokes the entry/exit handling and calls into the XEN handler on the interrupt stack if required. The exit code is slightly different from the regular idtentry_exit() on non-preemptible kernels. If the hypercall is preemptible and need_resched() is set then XEN provides a preempt hypercall scheduling function. Move this functionality into the entry code so it can use the existing idtentry functionality. [ mingo: Build fixes. ] Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Acked-by: Andy Lutomirski Acked-by: Juergen Gross Tested-by: Juergen Gross Link: https://lore.kernel.org/r/20200521202118.055270078@linutronix.de

sched/rt, xen: Use CONFIG_PREEMPTION

2019-12-08T13:37:36Z

CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT. Both PREEMPT and PREEMPT_RT require the same functionality which today depends on CONFIG_PREEMPT. Switch the preempt anand xen-ops code over to use CONFIG_PREEMPTION. Signed-off-by: Thomas Gleixner Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Reviewed-by: Juergen Gross Cc: Boris Ostrovsky Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stefano Stabellini Cc: xen-devel@lists.xenproject.org Link: https://lore.kernel.org/r/20191015191821.11479-23-bigeasy@linutronix.de Signed-off-by: Ingo Molnar

xen/efi: have a common runtime setup function

2019-10-02T14:31:07Z

Today the EFI runtime functions are setup in architecture specific code (x86 and arm), with the functions themselves living in drivers/xen as they are not architecture dependent. As the setup is exactly the same for arm and x86 move the setup to drivers/xen, too. This at once removes the need to make the single functions global visible. Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich [boris: "Dropped EXPORT_SYMBOL_GPL(xen_efi_runtime_setup)"] Signed-off-by: Boris Ostrovsky

xen: avoid link error on ARM

2019-07-31T06:14:12Z

Building the privcmd code as a loadable module on ARM, we get a link error due to the private cache management functions: ERROR: "__sync_icache_dcache" [drivers/xen/xen-privcmd.ko] undefined! Move the code into a new that is always built in when Xen is enabled, as suggested by Juergen Gross and Boris Ostrovsky. Signed-off-by: Arnd Bergmann Reviewed-by: Stefano Stabellini Signed-off-by: Juergen Gross

CONFIG_XEN_PV breaks xen_create_contiguous_region on ARM

2018-11-02T16:18:34Z

xen_create_contiguous_region has now only an implementation if CONFIG_XEN_PV is defined. However, on ARM we never set CONFIG_XEN_PV but we do have an implementation of xen_create_contiguous_region which is required for swiotlb-xen to work correctly (although it just sets *dma_handle). Cc: # 4.12 Fixes: 16624390816c ("xen: create xen_create/destroy_contiguous_region() stubs for PVHVM only builds") Signed-off-by: Stefano Stabellini Reviewed-by: Juergen Gross CC: Jeff.Kubascik@dornerworks.com CC: Jarvis.Roach@dornerworks.com CC: Nathan.Studer@dornerworks.com CC: vkuznets@redhat.com CC: boris.ostrovsky@oracle.com CC: jgross@suse.com CC: julien.grall@arm.com Signed-off-by: Juergen Gross

x86/xen: Move pv specific parts of arch/x86/xen/mmu.c to mmu_pv.c

2018-09-03T14:50:33Z

There are some PV specific functions in arch/x86/xen/mmu.c which can be moved to mmu_pv.c. This in turn enables to build multicalls.c dependent on CONFIG_XEN_PV. Signed-off-by: Juergen Gross Signed-off-by: Thomas Gleixner Reviewed-by: Boris Ostrovsky Cc: xen-devel@lists.xenproject.org Cc: virtualization@lists.linux-foundation.org Cc: akataria@vmware.com Cc: rusty@rustcorp.com.au Cc: hpa@zytor.com Link: https://lkml.kernel.org/r/20180828074026.820-3-jgross@suse.com

xen/privcmd: add IOCTL_PRIVCMD_MMAP_RESOURCE

2018-05-14T13:25:37Z

My recent Xen patch series introduces a new HYPERVISOR_memory_op to support direct priv-mapping of certain guest resources (such as ioreq pages, used by emulators) by a tools domain, rather than having to access such resources via the guest P2M. This patch adds the necessary infrastructure to the privcmd driver and Xen MMU code to support direct resource mapping. NOTE: The adjustment in the MMU code is partially cosmetic. Xen will now allow a PV tools domain to map guest pages either by GFN or MFN, thus the term 'mfn' has been swapped for 'pfn' in the lower layers of the remap code. Signed-off-by: Paul Durrant Reviewed-by: Boris Ostrovsky Signed-off-by: Juergen Gross

Merge tag 'for-linus-4.15-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2017-11-16T21:06:27Z

Pull xen updates from Juergen Gross: "Xen features and fixes for v4.15-rc1 Apart from several small fixes it contains the following features: - a series by Joao Martins to add vdso support of the pv clock interface - a series by Juergen Gross to add support for Xen pv guests to be able to run on 5 level paging hosts - a series by Stefano Stabellini adding the Xen pvcalls frontend driver using a paravirtualized socket interface" * tag 'for-linus-4.15-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (34 commits) xen/pvcalls: fix potential endless loop in pvcalls-front.c xen/pvcalls: Add MODULE_LICENSE() MAINTAINERS: xen, kvm: track pvclock-abi.h changes x86/xen/time: setup vcpu 0 time info page x86/xen/time: set pvclock flags on xen_time_init() x86/pvclock: add setter for pvclock_pvti_cpu0_va ptp_kvm: probe for kvm guest availability xen/privcmd: remove unused variable pageidx xen: select grant interface version xen: update arch/x86/include/asm/xen/cpuid.h xen: add grant interface version dependent constants to gnttab_ops xen: limit grant v2 interface to the v1 functionality xen: re-introduce support for grant v2 interface xen: support priv-mapping in an HVM tools domain xen/pvcalls: remove redundant check for irq >= 0 xen/pvcalls: fix unsigned less than zero error check xen/time: Return -ENODEV from xen_get_wallclock() xen/pvcalls-front: mark expected switch fall-through xen: xenbus_probe_frontend: mark expected switch fall-throughs xen/time: do not decrease steal time after live migration on xen ...

xen: support priv-mapping in an HVM tools domain

2017-11-03T20:53:53Z

If the domain has XENFEAT_auto_translated_physmap then use of the PV- specific HYPERVISOR_mmu_update hypercall is clearly incorrect. This patch adds checks in xen_remap_domain_gfn_array() and xen_unmap_domain_gfn_array() which call through to the approprate xlate_mmu function if the feature is present. A check is also added to xen_remap_domain_gfn_range() to fail with -EOPNOTSUPP since this should not be used in an HVM tools domain. Signed-off-by: Paul Durrant Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky

xen/time: do not decrease steal time after live migration on xen

2017-11-02T20:49:41Z

After guest live migration on xen, steal time in /proc/stat (cpustat[CPUTIME_STEAL]) might decrease because steal returned by xen_steal_lock() might be less than this_rq()->prev_steal_time which is derived from previous return value of xen_steal_clock(). For instance, steal time of each vcpu is 335 before live migration. cpu 198 0 368 200064 1962 0 0 1340 0 0 cpu0 38 0 81 50063 492 0 0 335 0 0 cpu1 65 0 97 49763 634 0 0 335 0 0 cpu2 38 0 81 50098 462 0 0 335 0 0 cpu3 56 0 107 50138 374 0 0 335 0 0 After live migration, steal time is reduced to 312. cpu 200 0 370 200330 1971 0 0 1248 0 0 cpu0 38 0 82 50123 500 0 0 312 0 0 cpu1 65 0 97 49832 634 0 0 312 0 0 cpu2 39 0 82 50167 462 0 0 312 0 0 cpu3 56 0 107 50207 374 0 0 312 0 0 Since runstate times are cumulative and cleared during xen live migration by xen hypervisor, the idea of this patch is to accumulate runstate times to global percpu variables before live migration suspend. Once guest VM is resumed, xen_get_runstate_snapshot_cpu() would always return the sum of new runstate times and previously accumulated times stored in global percpu variables. Comment above HYPERVISOR_suspend() has been removed as it is inaccurate: the call can return an error code (e.g., possibly -EPERM in the future). Similar and more severe issue would impact prior linux 4.8-4.10 as discussed by Michael Las at https://0xstubs.org/debugging-a-flaky-cpu-steal-time-counter-on-a-paravirtualized-xen-guest, which would overflow steal time and lead to 100% st usage in top command for linux 4.8-4.10. A backport of this patch would fix that issue. [boris: added linux/slab.h to driver/xen/time.c, slightly reformatted commit message] References: https://0xstubs.org/debugging-a-flaky-cpu-steal-time-counter-on-a-paravirtualized-xen-guest Signed-off-by: Dongli Zhang Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky