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2008-04-27KVM: SVM: do not intercept task switch with NPTJoerg Roedel
When KVM uses NPT there is no reason to intercept task switches. This patch removes the intercept for it in that case. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: Add kvm trace userspace interfaceFeng(Eric) Liu
This interface allows user a space application to read the trace of kvm related events through relayfs. Signed-off-by: Feng (Eric) Liu <eric.e.liu@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: ia64: Stub out kvmtraceAvi Kivity
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: s390: Stub out kvmtraceAvi Kivity
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: Add trace markersFeng (Eric) Liu
Trace markers allow userspace to trace execution of a virtual machine in order to monitor its performance. Signed-off-by: Feng (Eric) Liu <eric.e.liu@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: SVM: add intercept for machine check exceptionJoerg Roedel
To properly forward a MCE occured while the guest is running to the host, we have to intercept this exception and call the host handler by hand. This is implemented by this patch. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: SVM: align shadow CR4.MCE with hostJoerg Roedel
This patch aligns the host version of the CR4.MCE bit with the CR4 active in the guest. This is necessary to get MCE exceptions when the guest is running. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: SVM: indent svm_set_cr4 with tabs instead of spacesJoerg Roedel
The svm_set_cr4 function is indented with spaces. This patch replaces them with tabs. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: Register ioctl rangeAvi Kivity
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: MMU: Don't assume struct page for x86Anthony Liguori
This patch introduces a gfn_to_pfn() function and corresponding functions like kvm_release_pfn_dirty(). Using these new functions, we can modify the x86 MMU to no longer assume that it can always get a struct page for any given gfn. We don't want to eliminate gfn_to_page() entirely because a number of places assume they can do gfn_to_page() and then kmap() the results. When we support IO memory, gfn_to_page() will fail for IO pages although gfn_to_pfn() will succeed. This does not implement support for avoiding reference counting for reserved RAM or for IO memory. However, it should make those things pretty straight forward. Since we're only introducing new common symbols, I don't think it will break the non-x86 architectures but I haven't tested those. I've tested Intel, AMD, NPT, and hugetlbfs with Windows and Linux guests. [avi: fix overflow when shifting left pfns by adding casts] Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: ia64: Add a guide about how to create kvm guests on ia64Xiantao Zhang
Guide for creating virtual machine on kvm/ia64. Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: ia64: Enable kvm build for ia64Xiantao Zhang
Update the related Makefile and KConfig for kvm build Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: ia64: Add kvm sal/pal virtulization supportXiantao Zhang
Some sal/pal calls would be traped to kvm for virtulization from guest firmware. Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: ia64: Add guest interruption injection supportXiantao Zhang
process.c mainly handle interruption injection, and some faults handling. Signed-off-by: Anthony Xu <anthony.xu@intel.com> Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: ia64: Generate offset values for assembly code useXiantao Zhang
asm-offsets.c will generate offset values used for assembly code for some fileds of special structures. Signed-off-by: Anthony Xu <anthony.xu@intel.com> Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: ia64: Add optimization for some virtulization faultsXiantao Zhang
optvfault.S Add optimization for some performance-critical virtualization faults. Signed-off-by: Anthony Xu <anthony.xu@intel.com> Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: ia64: Add processor virtulization supportXiantao Zhang
vcpu.c provides processor virtualization logic for kvm. Signed-off-by: Anthony Xu <anthony.xu@intel.com> Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: ia64: Add trampoline for guest/host mode switchXiantao Zhang
trampoline code targets for guest/host world switch. Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: ia64: Add mmio decoder for kvm/ia64Xiantao Zhang
mmio.c includes mmio decoder, and related mmio logics. Signed-off-by: Anthony Xu <Anthony.xu@intel.com> Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: ia64: Add interruption vector table for vmmXiantao Zhang
vmm_ivt.S includes an ivt for vmm use. Signed-off-by: Anthony Xu <anthony.xu@intel.com> Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: ia64: Add TLB virtulization supportXiantao Zhang
vtlb.c includes tlb/VHPT virtulization. Signed-off-by: Anthony Xu <anthony.xu@intel.com> Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: ia64: VMM module interfacesXiantao Zhang
vmm.c adds the interfaces with kvm/module, and initialize global data area. Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: ia64: Add header files for kvm/ia64Xiantao Zhang
kvm_minstate.h : Marcos about Min save routines. lapic.h: apic structure definition. vcpu.h : routions related to vcpu virtualization. vti.h : Some macros or routines for VT support on Itanium. Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: ia64: Add kvm arch-specific core code for kvm/ia64Xiantao Zhang
kvm_ia64.c is created to handle kvm ia64-specific core logic. Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: ia64: Add header files for kvm/ia64Xiantao Zhang
Three header files are added: asm-ia64/kvm.h asm-ia64/kvm_host.h asm-ia64/kvm_para.h Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: ia64: Prepare some structure and routines for kvm useXiantao Zhang
Register structures are defined per SDM. Add three small routines for kernel: ia64_ttag, ia64_loadrs, ia64_flushrs Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: s390: Improve pgste accessesHeiko Carstens
There is no need to use interlocked updates when the rcp lock is held. Therefore the simple bitops variants can be used. This should improve performance. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: s390: rename stfl to kvm_stflHeiko Carstens
Temporarily rename this function to avoid merge conflicts and/or dependencies. This function will be removed as soon as git-s390 and kvm.git are finally upstream. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: s390: Fix incorrect return valueHeiko Carstens
kvm_arch_vcpu_ioctl_run currently incorrectly always returns 0. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: MMU: prepopulate guest pages after write-protectingMarcelo Tosatti
Zdenek reported a bug where a looping "dmsetup status" eventually hangs on SMP guests. The problem is that kvm_mmu_get_page() prepopulates the shadow MMU before write protecting the guest page tables. By doing so, it leaves a window open where the guest can mark a pte as present while the host has shadow cached such pte as "notrap". Accesses to such address will fault in the guest without the host having a chance to fix the situation. Fix by moving the write protection before the pte prefetch. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: MMU: Only mark_page_accessed() if the page was accessed by the guestAvi Kivity
If the accessed bit is not set, the guest has never accessed this page (at least through this spte), so there's no need to mark the page accessed. This provides more accurate data for the eviction algortithm. Noted by Andrea Arcangeli. Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: add vm refcountingIzik Eidus
the main purpose of adding this functions is the abilaty to release the spinlock that protect the kvm list while still be able to do operations on a specific kvm in a safe way. Signed-off-by: Izik Eidus <izike@qumranet.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: function declaration parameter name cleanupJoerg Roedel
The kvm_host.h file for x86 declares the functions kvm_set_cr[0348]. In the header file their second parameter is named cr0 in all cases. This patch renames the parameters so that they match the function name. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: Free apic access page on vm destructionAvi Kivity
Noticed by Marcelo Tosatti. Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: MMU: allow the vm to shrink the kvm mmu shadow cachesIzik Eidus
Allow the Linux memory manager to reclaim memory in the kvm shadow cache. Signed-off-by: Izik Eidus <izike@qumranet.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: MMU: unify slots_lock usageMarcelo Tosatti
Unify slots_lock acquision around vcpu_run(). This is simpler and less error-prone. Also fix some callsites that were not grabbing the lock properly. [avi: drop slots_lock while in guest mode to avoid holding the lock for indefinite periods] Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: VMX: Enable MSR Bitmap featureSheng Yang
MSR Bitmap controls whether the accessing of an MSR causes VM Exit. Eliminating exits on automatically saved and restored MSRs yields a small performance gain. Signed-off-by: Sheng Yang <sheng.yang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27s390: KVM guest: virtio device support, and kvm hypercallsChristian Borntraeger
This patch implements kvm guest kernel support for paravirtualized devices and contains two parts: o a basic virtio stub using virtio_ring and external interrupts and hypercalls o full hypercall implementation in kvm_para.h Currently we dont have PCI on s390. Making virtio_pci usable for s390 seems more complicated that providing an own stub. This virtio stub is similar to the lguest one, the memory for the descriptors and the device detection is made via additional mapped memory on top of the guest storage. We use an external interrupt with extint code 0x2603 for host->guest notification. The hypercall definition uses the diag instruction for issuing a hypercall. The parameters are written in R2-R7, the hypercall number is written in R1. This is similar to the system call ABI (svc) which can use R1 for the number and R2-R6 for the parameters. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27s390: KVM guest: detect when running on kvmCarsten Otte
This patch adds functionality to detect if the kernel runs under the KVM hypervisor. A macro MACHINE_IS_KVM is exported for device drivers. This allows drivers to skip device detection if the systems runs non-virtualized. We also define a preferred console to avoid having the ttyS0, which is a line mode only console. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: s390: update maintainersChristian Borntraeger
This patch adds an entry for kvm on s390 to the MAINTAINERS file :-). We intend to push all patches regarding this via Avi's kvm.git. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: s390: API documentationCarsten Otte
This patch adds Documentation/s390/kvm.txt, which describes specifics of kvm's user interface that are unique to s390 architecture. Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: s390: add kvm to kconfig on s390Christian Borntraeger
This patch adds the virtualization submenu and the kvm option to the kernel config. It also defines HAVE_KVM for 64bit kernels. Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: s390: intercepts for diagnose instructionsChristian Borntraeger
This patch introduces interpretation of some diagnose instruction intercepts. Diagnose is our classic architected way of doing a hypercall. This patch features the following diagnose codes: - vm storage size, that tells the guest about its memory layout - time slice end, which is used by the guest to indicate that it waits for a lock and thus cannot use up its time slice in a useful way - ipl functions, which a guest can use to reset and reboot itself In order to implement ipl functions, we also introduce an exit reason that causes userspace to perform various resets on the virtual machine. All resets are described in the principles of operation book, except KVM_S390_RESET_IPL which causes a reboot of the machine. Acked-by: Martin Schwidefsky <martin.schwidefsky@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: s390: interprocessor communication via sigpChristian Borntraeger
This patch introduces in-kernel handling of _some_ sigp interprocessor signals (similar to ipi). kvm_s390_handle_sigp() decodes the sigp instruction and calls individual handlers depending on the operation requested: - sigp sense tries to retrieve information such as existence or running state of the remote cpu - sigp emergency sends an external interrupt to the remove cpu - sigp stop stops a remove cpu - sigp stop store status stops a remote cpu, and stores its entire internal state to the cpus lowcore - sigp set arch sets the architecture mode of the remote cpu. setting to ESAME (s390x 64bit) is accepted, setting to ESA/S390 (s390, 31 or 24 bit) is denied, all others are passed to userland - sigp set prefix sets the prefix register of a remote cpu For implementation of this, the stop intercept indication starts to get reused on purpose: a set of action bits defines what to do once a cpu gets stopped: ACTION_STOP_ON_STOP really stops the cpu when a stop intercept is recognized ACTION_STORE_ON_STOP stores the cpu status to lowcore when a stop intercept is recognized Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: s390: intercepts for privileged instructionsChristian Borntraeger
This patch introduces in-kernel handling of some intercepts for privileged instructions: handle_set_prefix() sets the prefix register of the local cpu handle_store_prefix() stores the content of the prefix register to memory handle_store_cpu_address() stores the cpu number of the current cpu to memory handle_skey() just decrements the instruction address and retries handle_stsch() delivers condition code 3 "operation not supported" handle_chsc() same here handle_stfl() stores the facility list which contains the capabilities of the cpu handle_stidp() stores cpu type/model/revision and such handle_stsi() stores information about the system topology Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: s390: interrupt subsystem, cpu timer, waitpswCarsten Otte
This patch contains the s390 interrupt subsystem (similar to in kernel apic) including timer interrupts (similar to in-kernel-pit) and enabled wait (similar to in kernel hlt). In order to achieve that, this patch also introduces intercept handling for instruction intercepts, and it implements load control instructions. This patch introduces an ioctl KVM_S390_INTERRUPT which is valid for both the vm file descriptors and the vcpu file descriptors. In case this ioctl is issued against a vm file descriptor, the interrupt is considered floating. Floating interrupts may be delivered to any virtual cpu in the configuration. The following interrupts are supported: SIGP STOP - interprocessor signal that stops a remote cpu SIGP SET PREFIX - interprocessor signal that sets the prefix register of a (stopped) remote cpu INT EMERGENCY - interprocessor interrupt, usually used to signal need_reshed and for smp_call_function() in the guest. PROGRAM INT - exception during program execution such as page fault, illegal instruction and friends RESTART - interprocessor signal that starts a stopped cpu INT VIRTIO - floating interrupt for virtio signalisation INT SERVICE - floating interrupt for signalisations from the system service processor struct kvm_s390_interrupt, which is submitted as ioctl parameter when injecting an interrupt, also carrys parameter data for interrupts along with the interrupt type. Interrupts on s390 usually have a state that represents the current operation, or identifies which device has caused the interruption on s390. kvm_s390_handle_wait() does handle waitpsw in two flavors: in case of a disabled wait (that is, disabled for interrupts), we exit to userspace. In case of an enabled wait we set up a timer that equals the cpu clock comparator value and sleep on a wait queue. [christian: change virtio interrupt to 0x2603] Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: s390: sie intercept handlingChristian Borntraeger
This path introduces handling of sie intercepts in three flavors: Intercepts are either handled completely in-kernel by kvm_handle_sie_intercept(), or passed to userspace with corresponding data in struct kvm_run in case kvm_handle_sie_intercept() returns -ENOTSUPP. In case of partial execution in kernel with the need of userspace support, kvm_handle_sie_intercept() may choose to set up struct kvm_run and return -EREMOTE. The trivial intercept reasons are handled in this patch: handle_noop() just does nothing for intercepts that don't require our support at all handle_stop() is called when a cpu enters stopped state, and it drops out to userland after updating our vcpu state handle_validity() faults in the cpu lowcore if needed, or passes the request to userland Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27KVM: s390: arch backend for the kvm kernel moduleHeiko Carstens
This patch contains the port of Qumranet's kvm kernel module to IBM zSeries (aka s390x, mainframe) architecture. It uses the mainframe's virtualization instruction SIE to run virtual machines with up to 64 virtual CPUs each. This port is only usable on 64bit host kernels, and can only run 64bit guest kernels. However, running 31bit applications in guest userspace is possible. The following source files are introduced by this patch arch/s390/kvm/kvm-s390.c similar to arch/x86/kvm/x86.c, this implements all arch callbacks for kvm. __vcpu_run calls back into sie64a to enter the guest machine context arch/s390/kvm/sie64a.S assembler function sie64a, which enters guest context via SIE, and switches world before and after that include/asm-s390/kvm_host.h contains all vital data structures needed to run virtual machines on the mainframe include/asm-s390/kvm.h defines kvm_regs and friends for user access to guest register content arch/s390/kvm/gaccess.h functions similar to uaccess to access guest memory arch/s390/kvm/kvm-s390.h header file for kvm-s390 internals, extended by later patches Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27s390: KVM preparation: address of the 64bit extint parm in lowcoreChristian Borntraeger
The address 0x11b8 is used by z/VM for pfault and diag 250 I/O to provide a 64 bit extint parameter. virtio uses the same address, so its time to update the lowcore structure. Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27s390: KVM preparation: host memory management changes for s390 kvmChristian Borntraeger
This patch changes the s390 memory management defintions to use the pgste field for dirty and reference bit tracking of host and guest code. Usually on s390, dirty and referenced are tracked in storage keys, which belong to the physical page. This changes with virtualization: The guest and host dirty/reference bits are defined to be the logical OR of the values for the mapping and the physical page. This patch implements the necessary changes in pgtable.h for s390. There is a common code change in mm/rmap.c, the call to page_test_and_clear_young must be moved. This is a no-op for all architecture but s390. page_referenced checks the referenced bits for the physiscal page and for all mappings: o The physical page is checked with page_test_and_clear_young. o The mappings are checked with ptep_test_and_clear_young and friends. Without pgstes (the current implementation on Linux s390) the physical page check is implemented but the mapping callbacks are no-ops because dirty and referenced are not tracked in the s390 page tables. The pgstes introduces guest and host dirty and reference bits for s390 in the host mapping. These mapping must be checked before page_test_and_clear_young resets the reference bit. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>