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* KVM: MMU: fix release noslot pfnXiao Guangrong2012-10-22
| | | | | | | | | | We can not directly call kvm_release_pfn_clean to release the pfn since we can meet noslot pfn which is used to cache mmio info into spte Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Cc: stable@vger.kernel.org Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: MMU: Optimize is_last_gpte()Avi Kivity2012-09-20
| | | | | | | | | Instead of branchy code depending on level, gpte.ps, and mmu configuration, prepare everything in a bitmap during mode changes and look it up during runtime. Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: MMU: Optimize pte permission checksAvi Kivity2012-09-20
| | | | | | | | | | | | | | | | | | | | walk_addr_generic() permission checks are a maze of branchy code, which is performed four times per lookup. It depends on the type of access, efer.nxe, cr0.wp, cr4.smep, and in the near future, cr4.smap. Optimize this away by precalculating all variants and storing them in a bitmap. The bitmap is recalculated when rarely-changing variables change (cr0, cr4) and is indexed by the often-changing variables (page fault error code, pte access permissions). The permission check is moved to the end of the loop, otherwise an SMEP fault could be reported as a false positive, when PDE.U=1 but PTE.U=0. Noted by Xiao Guangrong. The result is short, branch-free code. Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: MMU: Move gpte_access() out of paging_tmpl.hAvi Kivity2012-09-20
| | | | | | | | | | We no longer rely on paging_tmpl.h defines; so we can move the function to mmu.c. Rely on zero extension to 64 bits to get the correct nx behaviour. Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: MMU: Push clean gpte write protection out of gpte_access()Avi Kivity2012-09-20
| | | | | | | | | | | | | | | | gpte_access() computes the access permissions of a guest pte and also write-protects clean gptes. This is wrong when we are servicing a write fault (since we'll be setting the dirty bit momentarily) but correct when instantiating a speculative spte, or when servicing a read fault (since we'll want to trap a following write in order to set the dirty bit). It doesn't seem to hurt in practice, but in order to make the code readable, push the write protection out of gpte_access() and into a new protect_clean_gpte() which is called explicitly when needed. Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: MMU: remove unnecessary checkXiao Guangrong2012-09-10
| | | | | | | | Checking the return of kvm_mmu_get_page is unnecessary since it is guaranteed by memory cache Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* Merge remote-tracking branch 'upstream/master' into queueMarcelo Tosatti2012-08-26
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merging critical fixes from upstream required for development. * upstream/master: (809 commits) libata: Add a space to " 2GB ATA Flash Disk" DMA blacklist entry Revert "powerpc: Update g5_defconfig" powerpc/perf: Use pmc_overflow() to detect rolled back events powerpc: Fix VMX in interrupt check in POWER7 copy loops powerpc: POWER7 copy_to_user/copy_from_user patch applied twice powerpc: Fix personality handling in ppc64_personality() powerpc/dma-iommu: Fix IOMMU window check powerpc: Remove unnecessary ifdefs powerpc/kgdb: Restore current_thread_info properly powerpc/kgdb: Bail out of KGDB when we've been triggered powerpc/kgdb: Do not set kgdb_single_step on ppc powerpc/mpic_msgr: Add missing includes powerpc: Fix null pointer deref in perf hardware breakpoints powerpc: Fixup whitespace in xmon powerpc: Fix xmon dl command for new printk implementation xfs: check for possible overflow in xfs_ioc_trim xfs: unlock the AGI buffer when looping in xfs_dialloc xfs: fix uninitialised variable in xfs_rtbuf_get() powerpc/fsl: fix "Failed to mount /dev: No such device" errors powerpc/fsl: update defconfigs ... Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| * KVM: MMU: Fix mmu_shrink() so that it can free mmu pages as intendedTakuya Yoshikawa2012-08-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Although the possible race described in commit 85b7059169e128c57a3a8a3e588fb89cb2031da1 KVM: MMU: fix shrinking page from the empty mmu was correct, the real cause of that issue was a more trivial bug of mmu_shrink() introduced by commit 1952639665e92481c34c34c3e2a71bf3e66ba362 KVM: MMU: do not iterate over all VMs in mmu_shrink() Here is the bug: if (kvm->arch.n_used_mmu_pages > 0) { if (!nr_to_scan--) break; continue; } We skip VMs whose n_used_mmu_pages is not zero and try to shrink others: in other words we try to shrink empty ones by mistake. This patch reverses the logic so that mmu_shrink() can free pages from the first VM whose n_used_mmu_pages is not zero. Note that we also add comments explaining the role of nr_to_scan which is not practically important now, hoping this will be improved in the future. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Cc: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* | KVM: introduce readonly memslotXiao Guangrong2012-08-22
| | | | | | | | | | | | | | | | | | | | | | | | | | In current code, if we map a readonly memory space from host to guest and the page is not currently mapped in the host, we will get a fault pfn and async is not allowed, then the vm will crash We introduce readonly memory region to map ROM/ROMD to the guest, read access is happy for readonly memslot, write access on readonly memslot will cause KVM_EXIT_MMIO exit Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* | KVM: introduce gfn_to_pfn_memslot_atomicXiao Guangrong2012-08-22
| | | | | | | | | | | | | | It can instead of hva_to_pfn_atomic Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* | KVM: do not release the error pfnXiao Guangrong2012-08-06
| | | | | | | | | | | | | | | | | | | | After commit a2766325cf9f9, the error pfn is replaced by the error code, it need not be released anymore [ The patch has been compiling tested for powerpc ] Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* | KVM: introduce KVM_PFN_ERR_HWPOISONXiao Guangrong2012-08-06
| | | | | | | | | | | | | | Then, get_hwpoison_pfn and is_hwpoison_pfn can be removed Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* | KVM: introduce KVM_PFN_ERR_FAULTXiao Guangrong2012-08-06
| | | | | | | | | | | | | | | | After that, the exported and un-inline function, get_fault_pfn, can be removed Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* | KVM: Push rmap into kvm_arch_memory_slotTakuya Yoshikawa2012-08-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Two reasons: - x86 can integrate rmap and rmap_pde and remove heuristics in __gfn_to_rmap(). - Some architectures do not need rmap. Since rmap is one of the most memory consuming stuff in KVM, ppc'd better restrict the allocation to Book3S HV. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Acked-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Avi Kivity <avi@redhat.com>
* | KVM: MMU: Use gfn_to_rmap() instead of directly reading rmap arrayTakuya Yoshikawa2012-08-06
| | | | | | | | | | | | | | This helps to make rmap architecture specific in a later patch. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: Avi Kivity <avi@redhat.com>
* | KVM: MMU: use kvm_release_pfn_clean to release pfnXiao Guangrong2012-07-26
| | | | | | | | | | | | | | | | | | | | The current code depends on the fact that fault_page is the normal page, however, we will use the error code instead of these dummy pages in the later patch, so we use kvm_release_pfn_clean to release pfn which will release the error code properly Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* | Merge branch 'queue' into nextAvi Kivity2012-07-26
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge patches queued during the run-up to the merge window. * queue: (25 commits) KVM: Choose better candidate for directed yield KVM: Note down when cpu relax intercepted or pause loop exited KVM: Add config to support ple or cpu relax optimzation KVM: switch to symbolic name for irq_states size KVM: x86: Fix typos in pmu.c KVM: x86: Fix typos in lapic.c KVM: x86: Fix typos in cpuid.c KVM: x86: Fix typos in emulate.c KVM: x86: Fix typos in x86.c KVM: SVM: Fix typos KVM: VMX: Fix typos KVM: remove the unused parameter of gfn_to_pfn_memslot KVM: remove is_error_hpa KVM: make bad_pfn static to kvm_main.c KVM: using get_fault_pfn to get the fault pfn KVM: MMU: track the refcount when unmap the page KVM: x86: remove unnecessary mark_page_dirty KVM: MMU: Avoid handling same rmap_pde in kvm_handle_hva_range() KVM: MMU: Push trace_kvm_age_page() into kvm_age_rmapp() KVM: MMU: Add memslot parameter to hva handlers ... Signed-off-by: Avi Kivity <avi@redhat.com>
| * KVM: remove the unused parameter of gfn_to_pfn_memslotXiao Guangrong2012-07-19
| | | | | | | | | | | | | | | | The parameter, 'kvm', is not used in gfn_to_pfn_memslot, we can happily remove it Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| * KVM: using get_fault_pfn to get the fault pfnXiao Guangrong2012-07-19
| | | | | | | | | | | | | | Using get_fault_pfn to cleanup the code Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| * KVM: MMU: track the refcount when unmap the pageXiao Guangrong2012-07-19
| | | | | | | | | | | | | | | | It will trigger a WARN_ON if the page has been freed but it is still used in mmu, it can help us to detect mm bug early Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| * KVM: MMU: Avoid handling same rmap_pde in kvm_handle_hva_range()Takuya Yoshikawa2012-07-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we invalidate a THP page, we call the handler with the same rmap_pde argument 512 times in the following loop: for each guest page in the range for each level unmap using rmap This patch avoids these extra handler calls by changing the loop order like this: for each level for each rmap in the range unmap using rmap With the preceding patches in the patch series, this made THP page invalidation more than 5 times faster on our x86 host: the host became more responsive during swapping the guest's memory as a result. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| * KVM: MMU: Push trace_kvm_age_page() into kvm_age_rmapp()Takuya Yoshikawa2012-07-18
| | | | | | | | | | | | | | | | This restricts the tracing to page aging and makes it possible to optimize kvm_handle_hva_range() further in the following patch. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| * KVM: MMU: Add memslot parameter to hva handlersTakuya Yoshikawa2012-07-18
| | | | | | | | | | | | | | | | This is needed to push trace_kvm_age_page() into kvm_age_rmapp() in the following patch. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| * KVM: Separate rmap_pde from kvm_lpage_info->write_countTakuya Yoshikawa2012-07-18
| | | | | | | | | | | | | | | | | | This makes it possible to loop over rmap_pde arrays in the same way as we do over rmap so that we can optimize kvm_handle_hva_range() easily in the following patch. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| * KVM: Introduce kvm_unmap_hva_range() for ↵Takuya Yoshikawa2012-07-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kvm_mmu_notifier_invalidate_range_start() When we tested KVM under memory pressure, with THP enabled on the host, we noticed that MMU notifier took a long time to invalidate huge pages. Since the invalidation was done with mmu_lock held, it not only wasted the CPU but also made the host harder to respond. This patch mitigates this by using kvm_handle_hva_range(). Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Cc: Alexander Graf <agraf@suse.de> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| * KVM: MMU: Make kvm_handle_hva() handle range of addressesTakuya Yoshikawa2012-07-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When guest's memory is backed by THP pages, MMU notifier needs to call kvm_unmap_hva(), which in turn leads to kvm_handle_hva(), in a loop to invalidate a range of pages which constitute one huge page: for each page for each memslot if page is in memslot unmap using rmap This means although every page in that range is expected to be found in the same memslot, we are forced to check unrelated memslots many times. If the guest has more memslots, the situation will become worse. Furthermore, if the range does not include any pages in the guest's memory, the loop over the pages will just consume extra time. This patch, together with the following patches, solves this problem by introducing kvm_handle_hva_range() which makes the loop look like this: for each memslot for each page in memslot unmap using rmap In this new processing, the actual work is converted to a loop over rmap which is much more cache friendly than before. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Cc: Alexander Graf <agraf@suse.de> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| * KVM: Introduce hva_to_gfn_memslot() for kvm_handle_hva()Takuya Yoshikawa2012-07-18
| | | | | | | | | | | | | | | | | | | | | | This restricts hva handling in mmu code and makes it easier to extend kvm_handle_hva() so that it can treat a range of addresses later in this patch series. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Cc: Alexander Graf <agraf@suse.de> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| * KVM: MMU: Use __gfn_to_rmap() to clean up kvm_handle_hva()Takuya Yoshikawa2012-07-18
| | | | | | | | | | | | | | We can treat every level uniformly. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
* | Merge tag 'kvm-3.6-1' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds2012-07-24
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull KVM updates from Avi Kivity: "Highlights include - full big real mode emulation on pre-Westmere Intel hosts (can be disabled with emulate_invalid_guest_state=0) - relatively small ppc and s390 updates - PCID/INVPCID support in guests - EOI avoidance; 3.6 guests should perform better on 3.6 hosts on interrupt intensive workloads) - Lockless write faults during live migration - EPT accessed/dirty bits support for new Intel processors" Fix up conflicts in: - Documentation/virtual/kvm/api.txt: Stupid subchapter numbering, added next to each other. - arch/powerpc/kvm/booke_interrupts.S: PPC asm changes clashing with the KVM fixes - arch/s390/include/asm/sigp.h, arch/s390/kvm/sigp.c: Duplicated commits through the kvm tree and the s390 tree, with subsequent edits in the KVM tree. * tag 'kvm-3.6-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (93 commits) KVM: fix race with level interrupts x86, hyper: fix build with !CONFIG_KVM_GUEST Revert "apic: fix kvm build on UP without IOAPIC" KVM guest: switch to apic_set_eoi_write, apic_write apic: add apic_set_eoi_write for PV use KVM: VMX: Implement PCID/INVPCID for guests with EPT KVM: Add x86_hyper_kvm to complete detect_hypervisor_platform check KVM: PPC: Critical interrupt emulation support KVM: PPC: e500mc: Fix tlbilx emulation for 64-bit guests KVM: PPC64: booke: Set interrupt computation mode for 64-bit host KVM: PPC: bookehv: Add ESR flag to Data Storage Interrupt KVM: PPC: bookehv64: Add support for std/ld emulation. booke: Added crit/mc exception handler for e500v2 booke/bookehv: Add host crit-watchdog exception support KVM: MMU: document mmu-lock and fast page fault KVM: MMU: fix kvm_mmu_pagetable_walk tracepoint KVM: MMU: trace fast page fault KVM: MMU: fast path of handling guest page fault KVM: MMU: introduce SPTE_MMU_WRITEABLE bit KVM: MMU: fold tlb flush judgement into mmu_spte_update ...
| * KVM: MMU: trace fast page faultXiao Guangrong2012-07-11
| | | | | | | | | | | | | | To see what happen on this path and help us to optimize it Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
| * KVM: MMU: fast path of handling guest page faultXiao Guangrong2012-07-11
| | | | | | | | | | | | | | | | | | | | | | | | If the the present bit of page fault error code is set, it indicates the shadow page is populated on all levels, it means what we do is only modify the access bit which can be done out of mmu-lock Currently, in order to simplify the code, we only fix the page fault caused by write-protect on the fast path Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
| * KVM: MMU: introduce SPTE_MMU_WRITEABLE bitXiao Guangrong2012-07-11
| | | | | | | | | | | | | | | | | | | | | | | | This bit indicates whether the spte can be writable on MMU, that means the corresponding gpte is writable and the corresponding gfn is not protected by shadow page protection In the later path, SPTE_MMU_WRITEABLE will indicates whether the spte can be locklessly updated Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
| * KVM: MMU: fold tlb flush judgement into mmu_spte_updateXiao Guangrong2012-07-11
| | | | | | | | | | | | | | mmu_spte_update() is the common function, we can easily audit the path Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
| * KVM: MMU: cleanup spte_write_protectXiao Guangrong2012-07-11
| | | | | | | | | | | | | | Use __drop_large_spte to cleanup this function and comment spte_write_protect Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
| * KVM: MMU: abstract spte write-protectXiao Guangrong2012-07-11
| | | | | | | | | | | | | | | | Introduce a common function to abstract spte write-protect to cleanup the code Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
| * KVM: MMU: return bool in __rmap_write_protectXiao Guangrong2012-07-11
| | | | | | | | | | | | | | | | The reture value of __rmap_write_protect is either 1 or 0, use true/false instead of these Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
| * KVM: MMU: Force cr3 reload with two dimensional paging on mov cr3 emulationAvi Kivity2012-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently the MMU's ->new_cr3() callback does nothing when guest paging is disabled or when two-dimentional paging (e.g. EPT on Intel) is active. This means that an emulated write to cr3 can be lost; kvm_set_cr3() will write vcpu-arch.cr3, but the GUEST_CR3 field in the VMCS will retain its old value and this is what the guest sees. This bug did not have any effect until now because: - with unrestricted guest, or with svm, we never emulate a mov cr3 instruction - without unrestricted guest, and with paging enabled, we also never emulate a mov cr3 instruction - without unrestricted guest, but with paging disabled, the guest's cr3 is ignored until the guest enables paging; at this point the value from arch.cr3 is loaded correctly my the mov cr0 instruction which turns on paging However, the patchset that enables big real mode causes us to emulate mov cr3 instructions in protected mode sometimes (when guest state is not virtualizable by vmx); this mov cr3 is effectively ignored and will crash the guest. The fix is to make nonpaging_new_cr3() call mmu_free_roots() to force a cr3 reload. This is awkward because now all the new_cr3 callbacks to the same thing, and because mmu_free_roots() is somewhat of an overkill; but fixing that is more complicated and will be done after this minimal fix. Observed in the Window XP 32-bit installer while bringing up secondary vcpus. Signed-off-by: Avi Kivity <avi@redhat.com>
| * KVM: x86: change PT_FIRST_AVAIL_BITS_SHIFT to avoid conflict with EPT Dirty bitXudong Hao2012-06-13
| | | | | | | | | | | | | | | | | | EPT Dirty bit use bit 9 as Intel SDM definition, to avoid conflict, change PT_FIRST_AVAIL_BITS_SHIFT to 10. Signed-off-by: Xudong Hao <xudong.hao@intel.com> Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| * KVM: MMU: Remove unused parameter from mmu_memory_cache_alloc()Takuya Yoshikawa2012-06-11
| | | | | | | | | | | | | | Size is not needed to return one from pre-allocated objects. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| * KVM: disable uninitialized var warningMichael S. Tsirkin2012-06-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I see this in 3.5-rc1: arch/x86/kvm/mmu.c: In function ‘kvm_test_age_rmapp’: arch/x86/kvm/mmu.c:1271: warning: ‘iter.desc’ may be used uninitialized in this function The line in question was introduced by commit 1e3f42f03c38c29c1814199a6f0a2f01b919ea3f static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp, unsigned long data) { - u64 *spte; + u64 *sptep; + struct rmap_iterator iter; <- line 1271 int young = 0; /* The reason I think is that the compiler assumes that the rmap value could be 0, so static u64 *rmap_get_first(unsigned long rmap, struct rmap_iterator *iter) { if (!rmap) return NULL; if (!(rmap & 1)) { iter->desc = NULL; return (u64 *)rmap; } iter->desc = (struct pte_list_desc *)(rmap & ~1ul); iter->pos = 0; return iter->desc->sptes[iter->pos]; } will not initialize iter.desc, but the compiler isn't smart enough to see that for (sptep = rmap_get_first(*rmapp, &iter); sptep; sptep = rmap_get_next(&iter)) { will immediately exit in this case. I checked by adding if (!*rmapp) goto out; on top which is clearly equivalent but disables the warning. This patch uses uninitialized_var to disable the warning without increasing code size. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
| * KVM: MMU: do not iterate over all VMs in mmu_shrink()Gleb Natapov2012-06-05
| | | | | | | | | | | | | | | | | | mmu_shrink() needlessly iterates over all VMs even though it will not attempt to free mmu pages from more than one on them. Fix that and also check used mmu pages count outside of VM lock to skip inactive VMs faster. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
| * KVM: VMX: Use EPT Access bit in response to memory notifiersXudong Hao2012-06-05
| | | | | | | | | | | | Signed-off-by: Haitao Shan <haitao.shan@intel.com> Signed-off-by: Xudong Hao <xudong.hao@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* | KVM: MMU: fix shrinking page from the empty mmuXiao Guangrong2012-07-03
|/ | | | | | | | | | | | | | | | | | | | | | | | | Fix: [ 3190.059226] BUG: unable to handle kernel NULL pointer dereference at (null) [ 3190.062224] IP: [<ffffffffa02aac66>] mmu_page_zap_pte+0x10/0xa7 [kvm] [ 3190.063760] PGD 104f50067 PUD 112bea067 PMD 0 [ 3190.065309] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC [ 3190.066860] CPU 1 [ ...... ] [ 3190.109629] Call Trace: [ 3190.111342] [<ffffffffa02aada6>] kvm_mmu_prepare_zap_page+0xa9/0x1fc [kvm] [ 3190.113091] [<ffffffffa02ab2f5>] mmu_shrink+0x11f/0x1f3 [kvm] [ 3190.114844] [<ffffffffa02ab25d>] ? mmu_shrink+0x87/0x1f3 [kvm] [ 3190.116598] [<ffffffff81150c9d>] ? prune_super+0x142/0x154 [ 3190.118333] [<ffffffff8110a4f4>] ? shrink_slab+0x39/0x31e [ 3190.120043] [<ffffffff8110a687>] shrink_slab+0x1cc/0x31e [ 3190.121718] [<ffffffff8110ca1d>] do_try_to_free_pages This is caused by shrinking page from the empty mmu, although we have checked n_used_mmu_pages, it is useless since the check is out of mmu-lock Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
* KVM: MMU: fix huge page adapted on non-PAE hostXiao Guangrong2012-05-28
| | | | | | | | | The huge page size is 4M on non-PAE host, but 2M page size is used in transparent_hugepage_adjust(), so the page we get after adjust the mapping level is not the head page, the BUG_ON() will be triggered Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: MMU: Don't use RCU for lockless shadow walkingAvi Kivity2012-05-16
| | | | | | | | | | | | | | | | | | Using RCU for lockless shadow walking can increase the amount of memory in use by the system, since RCU grace periods are unpredictable. We also have an unconditional write to a shared variable (reader_counter), which isn't good for scaling. Replace that with a scheme similar to x86's get_user_pages_fast(): disable interrupts during lockless shadow walk to force the freer (kvm_mmu_commit_zap_page()) to wait for the TLB flush IPI to find the processor with interrupts enabled. We also add a new vcpu->mode, READING_SHADOW_PAGE_TABLES, to prevent kvm_flush_remote_tlbs() from avoiding the IPI. Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
* KVM: MMU: use page table level macroDavidlohr Bueso2012-04-18
| | | | | | | Its much cleaner to use PT_PAGE_TABLE_LEVEL than its numeric value. Signed-off-by: Davidlohr Bueso <dave@gnu.org> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
* KVM: MMU: Improve iteration through sptes from rmapTakuya Yoshikawa2012-04-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Iteration using rmap_next(), the actual body is pte_list_next(), is inefficient: every time we call it we start from checking whether rmap holds a single spte or points to a descriptor which links more sptes. In the case of shadow paging, this quadratic total iteration cost is a problem. Even for two dimensional paging, with EPT/NPT on, in which we almost always have a single mapping, the extra checks at the end of the iteration should be eliminated. This patch fixes this by introducing rmap_iterator which keeps the iteration context for the next search. Furthermore the implementation of rmap_next() is splitted into two functions, rmap_get_first() and rmap_get_next(), to avoid repeatedly checking whether the rmap being iterated on has only one spte. Although there seemed to be only a slight change for EPT/NPT, the actual improvement was significant: we observed that GET_DIRTY_LOG for 1GB dirty memory became 15% faster than before. This is probably because the new code is easy to make branch predictions. Note: we just remove pte_list_next() because we can think of parent_ptes as a reverse mapping. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: MMU: Make pte_list_desc fit cache lines wellTakuya Yoshikawa2012-04-08
| | | | | | | | | | | | | | | | | | We have PTE_LIST_EXT + 1 pointers in this structure and these 40/20 bytes do not fit cache lines well. Furthermore, some allocators may use 64/32-byte objects for the pte_list_desc cache. This patch solves this problem by changing PTE_LIST_EXT from 4 to 3. For shadow paging, the new size is still large enough to hold both the kernel and process mappings for usual anonymous pages. For file mappings, there may be a slight change in the cache usage. Note: with EPT/NPT we almost always have a single spte in each reverse mapping and we will not see any change by this. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: Avoid checking huge page mappings in get_dirty_log()Takuya Yoshikawa2012-04-08
| | | | | | | | | | | | | Dropped such mappings when we enabled dirty logging and we will never create new ones until we stop the logging. For this we introduce a new function which can be used to write protect a range of PT level pages: although we do not need to care about a range of pages at this point, the following patch will need this feature to optimize the write protection of many pages. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: Avi Kivity <avi@redhat.com>
* KVM: MMU: Split the main body of rmap_write_protect() off from othersTakuya Yoshikawa2012-04-08
| | | | | | | | | | | We will use this in the following patch to implement another function which needs to write protect pages using the rmap information. Note that there is a small change in debug printing for large pages: we do not differentiate them from others to avoid duplicating code. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: Avi Kivity <avi@redhat.com>
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