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2013-03-19KVM: x86: Convert MSR_KVM_SYSTEM_TIME to use gfn_to_hva_cache functions ↵Andy Honig
(CVE-2013-1797) There is a potential use after free issue with the handling of MSR_KVM_SYSTEM_TIME. If the guest specifies a GPA in a movable or removable memory such as frame buffers then KVM might continue to write to that address even after it's removed via KVM_SET_USER_MEMORY_REGION. KVM pins the page in memory so it's unlikely to cause an issue, but if the user space component re-purposes the memory previously used for the guest, then the guest will be able to corrupt that memory. Tested: Tested against kvmclock unit test Signed-off-by: Andrew Honig <ahonig@google.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-03-19KVM: x86: fix for buffer overflow in handling of MSR_KVM_SYSTEM_TIME ↵Andy Honig
(CVE-2013-1796) If the guest sets the GPA of the time_page so that the request to update the time straddles a page then KVM will write onto an incorrect page. The write is done byusing kmap atomic to get a pointer to the page for the time structure and then performing a memcpy to that page starting at an offset that the guest controls. Well behaved guests always provide a 32-byte aligned address, however a malicious guest could use this to corrupt host kernel memory. Tested: Tested against kvmclock unit test. Signed-off-by: Andrew Honig <ahonig@google.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-03-18KVM: x86: fix deadlock in clock-in-progress request handlingMarcelo Tosatti
There is a deadlock in pvclock handling: cpu0: cpu1: kvm_gen_update_masterclock() kvm_guest_time_update() spin_lock(pvclock_gtod_sync_lock) local_irq_save(flags) spin_lock(pvclock_gtod_sync_lock) kvm_make_mclock_inprogress_request(kvm) make_all_cpus_request() smp_call_function_many() Now if smp_call_function_many() called by cpu0 tries to call function on cpu1 there will be a deadlock. Fix by moving pvclock_gtod_sync_lock protected section outside irq disabled section. Analyzed by Gleb Natapov <gleb@redhat.com> Acked-by: Gleb Natapov <gleb@redhat.com> Reported-and-Tested-by: Yongjie Ren <yongjie.ren@intel.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-02-27hlist: drop the node parameter from iteratorsSasha Levin
I'm not sure why, but the hlist for each entry iterators were conceived list_for_each_entry(pos, head, member) The hlist ones were greedy and wanted an extra parameter: hlist_for_each_entry(tpos, pos, head, member) Why did they need an extra pos parameter? I'm not quite sure. Not only they don't really need it, it also prevents the iterator from looking exactly like the list iterator, which is unfortunate. Besides the semantic patch, there was some manual work required: - Fix up the actual hlist iterators in linux/list.h - Fix up the declaration of other iterators based on the hlist ones. - A very small amount of places were using the 'node' parameter, this was modified to use 'obj->member' instead. - Coccinelle didn't handle the hlist_for_each_entry_safe iterator properly, so those had to be fixed up manually. The semantic patch which is mostly the work of Peter Senna Tschudin is here: @@ iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host; type T; expression a,c,d,e; identifier b; statement S; @@ -T b; <+... when != b ( hlist_for_each_entry(a, - b, c, d) S | hlist_for_each_entry_continue(a, - b, c) S | hlist_for_each_entry_from(a, - b, c) S | hlist_for_each_entry_rcu(a, - b, c, d) S | hlist_for_each_entry_rcu_bh(a, - b, c, d) S | hlist_for_each_entry_continue_rcu_bh(a, - b, c) S | for_each_busy_worker(a, c, - b, d) S | ax25_uid_for_each(a, - b, c) S | ax25_for_each(a, - b, c) S | inet_bind_bucket_for_each(a, - b, c) S | sctp_for_each_hentry(a, - b, c) S | sk_for_each(a, - b, c) S | sk_for_each_rcu(a, - b, c) S | sk_for_each_from -(a, b) +(a) S + sk_for_each_from(a) S | sk_for_each_safe(a, - b, c, d) S | sk_for_each_bound(a, - b, c) S | hlist_for_each_entry_safe(a, - b, c, d, e) S | hlist_for_each_entry_continue_rcu(a, - b, c) S | nr_neigh_for_each(a, - b, c) S | nr_neigh_for_each_safe(a, - b, c, d) S | nr_node_for_each(a, - b, c) S | nr_node_for_each_safe(a, - b, c, d) S | - for_each_gfn_sp(a, c, d, b) S + for_each_gfn_sp(a, c, d) S | - for_each_gfn_indirect_valid_sp(a, c, d, b) S + for_each_gfn_indirect_valid_sp(a, c, d) S | for_each_host(a, - b, c) S | for_each_host_safe(a, - b, c, d) S | for_each_mesh_entry(a, - b, c, d) S ) ...+> [akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c] [akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c] [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: fix warnings] [akpm@linux-foudnation.org: redo intrusive kvm changes] Tested-by: Peter Senna Tschudin <peter.senna@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-24Merge tag 'kvm-3.9-1' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull KVM updates from Marcelo Tosatti: "KVM updates for the 3.9 merge window, including x86 real mode emulation fixes, stronger memory slot interface restrictions, mmu_lock spinlock hold time reduction, improved handling of large page faults on shadow, initial APICv HW acceleration support, s390 channel IO based virtio, amongst others" * tag 'kvm-3.9-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (143 commits) Revert "KVM: MMU: lazily drop large spte" x86: pvclock kvm: align allocation size to page size KVM: nVMX: Remove redundant get_vmcs12 from nested_vmx_exit_handled_msr x86 emulator: fix parity calculation for AAD instruction KVM: PPC: BookE: Handle alignment interrupts booke: Added DBCR4 SPR number KVM: PPC: booke: Allow multiple exception types KVM: PPC: booke: use vcpu reference from thread_struct KVM: Remove user_alloc from struct kvm_memory_slot KVM: VMX: disable apicv by default KVM: s390: Fix handling of iscs. KVM: MMU: cleanup __direct_map KVM: MMU: remove pt_access in mmu_set_spte KVM: MMU: cleanup mapping-level KVM: MMU: lazily drop large spte KVM: VMX: cleanup vmx_set_cr0(). KVM: VMX: add missing exit names to VMX_EXIT_REASONS array KVM: VMX: disable SMEP feature when guest is in non-paging mode KVM: Remove duplicate text in api.txt Revert "KVM: MMU: split kvm_mmu_free_page" ...
2013-02-20Revert "KVM: MMU: lazily drop large spte"Marcelo Tosatti
This reverts commit caf6900f2d8aaebe404c976753f6813ccd31d95e. It is causing migration failures, reference https://bugzilla.kernel.org/show_bug.cgi?id=54061. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-02-19x86, kvm: Add MSR_AMD64_BU_CFG2 to the list of ignored MSRsBorislav Petkov
The "x86, AMD: Enable WC+ memory type on family 10 processors" patch currently in -tip added a workaround for AMD F10h CPUs which #GPs my guest when booted in kvm. This is because it accesses MSR_AMD64_BU_CFG2 which is not currently ignored by kvm. Do that because this MSR is only baremetal-relevant anyway. While at it, move the ignored MSRs at the beginning of kvm_set_msr_common so that we exit then and there. Acked-by: Gleb Natapov <gleb@redhat.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Andre Przywara <andre@andrep.de> Cc: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/1361298793-31834-2-git-send-email-bp@alien8.de Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-02-14KVM: nVMX: Remove redundant get_vmcs12 from nested_vmx_exit_handled_msrJan Kiszka
We already pass vmcs12 as argument. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
2013-02-13x86 emulator: fix parity calculation for AAD instructionGleb Natapov
Reported-by: Paolo Bonzini <pbonzini@redhat.com> Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
2013-02-11KVM: Remove user_alloc from struct kvm_memory_slotTakuya Yoshikawa
This field was needed to differentiate memory slots created by the new API, KVM_SET_USER_MEMORY_REGION, from those by the old equivalent, KVM_SET_MEMORY_REGION, whose support was dropped long before: commit b74a07beed0e64bfba413dcb70dd6749c57f43dc KVM: Remove kernel-allocated memory regions Although we also have private memory slots to which KVM allocates memory with vm_mmap(), !user_alloc slots in other words, the slot id should be enough for differentiating them. Note: corresponding function parameters will be removed later. Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Gleb Natapov <gleb@redhat.com>
2013-02-11KVM: VMX: disable apicv by defaultYang Zhang
Without Posted Interrupt, current code is broken. Just disable by default until Posted Interrupt is ready. Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
2013-02-06KVM: MMU: cleanup __direct_mapXiao Guangrong
Use link_shadow_page to link the sp to the spte in __direct_map Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-02-06KVM: MMU: remove pt_access in mmu_set_spteXiao Guangrong
It is only used in debug code, so drop it Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-02-06KVM: MMU: cleanup mapping-levelXiao Guangrong
Use min() to cleanup mapping_level Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-02-06KVM: MMU: lazily drop large spteXiao Guangrong
Currently, kvm zaps the large spte if write-protected is needed, the later read can fault on that spte. Actually, we can make the large spte readonly instead of making them not present, the page fault caused by read access can be avoided The idea is from Avi: | As I mentioned before, write-protecting a large spte is a good idea, | since it moves some work from protect-time to fault-time, so it reduces | jitter. This removes the need for the return value. Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-02-06KVM: VMX: cleanup vmx_set_cr0().Gleb Natapov
When calculating hw_cr0 teh current code masks bits that should be always on and re-adds them back immediately after. Cleanup the code by masking only those bits that should be dropped from hw_cr0. This allow us to get rid of some defines. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-02-05KVM: VMX: disable SMEP feature when guest is in non-paging modeDongxiao Xu
SMEP is disabled if CPU is in non-paging mode in hardware. However KVM always uses paging mode to emulate guest non-paging mode with TDP. To emulate this behavior, SMEP needs to be manually disabled when guest switches to non-paging mode. We met an issue that, SMP Linux guest with recent kernel (enable SMEP support, for example, 3.5.3) would crash with triple fault if setting unrestricted_guest=0. This is because KVM uses an identity mapping page table to emulate the non-paging mode, where the page table is set with USER flag. If SMEP is still enabled in this case, guest will meet unhandlable page fault and then crash. Reviewed-by: Gleb Natapov <gleb@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Dongxiao Xu <dongxiao.xu@intel.com> Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-02-05Revert "KVM: MMU: split kvm_mmu_free_page"Gleb Natapov
This reverts commit bd4c86eaa6ff10abc4e00d0f45d2a28b10b09df4. There is not user for kvm_mmu_isolate_page() any more. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-02-04KVM: MMU: drop superfluous is_present_gpte() check.Gleb Natapov
Gust page walker puts only present ptes into ptes[] array. No need to check it again. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-02-04KVM: MMU: drop superfluous min() call.Gleb Natapov
Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-02-04KVM: MMU: set base_role.nxe during mmu initialization.Gleb Natapov
Move base_role.nxe initialisation to where all other roles are initialized. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-02-04KVM: MMU: drop unneeded checks.Gleb Natapov
Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-02-04KVM: MMU: make spte_is_locklessly_modifiable() more clearGleb Natapov
spte_is_locklessly_modifiable() checks that both SPTE_HOST_WRITEABLE and SPTE_MMU_WRITEABLE are present on spte. Make it more explicit. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-29x86, apicv: add virtual interrupt delivery supportYang Zhang
Virtual interrupt delivery avoids KVM to inject vAPIC interrupts manually, which is fully taken care of by the hardware. This needs some special awareness into existing interrupr injection path: - for pending interrupt, instead of direct injection, we may need update architecture specific indicators before resuming to guest. - A pending interrupt, which is masked by ISR, should be also considered in above update action, since hardware will decide when to inject it at right time. Current has_interrupt and get_interrupt only returns a valid vector from injection p.o.v. Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
2013-01-29x86, apicv: add virtual x2apic supportYang Zhang
basically to benefit from apicv, we need to enable virtualized x2apic mode. Currently, we only enable it when guest is really using x2apic. Also, clear MSR bitmap for corresponding x2apic MSRs when guest enabled x2apic: 0x800 - 0x8ff: no read intercept for apicv register virtualization, except APIC ID and TMCCT which need software's assistance to get right value. Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
2013-01-29x86, apicv: add APICv register virtualization supportYang Zhang
- APIC read doesn't cause VM-Exit - APIC write becomes trap-like Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Yang Zhang <yang.z.zhang@intel.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
2013-01-27KVM: x86 emulator: fix test_cc() build failure on i386Avi Kivity
'pushq' doesn't exist on i386. Replace with 'push', which should work since the operand is a register. Signed-off-by: Avi Kivity <avi.kivity@gmail.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
2013-01-24KVM: VMX: set vmx->emulation_required only when needed.Gleb Natapov
If emulate_invalid_guest_state=false vmx->emulation_required is never actually used, but it ends up to be always set to true since handle_invalid_guest_state(), the only place it is reset back to false, is never called. This, besides been not very clean, makes vmexit and vmentry path to check emulate_invalid_guest_state needlessly. The patch fixes that by keeping emulation_required coherent with emulate_invalid_guest_state setting. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-24KVM: x86: fix use of uninitialized memory as segment descriptor in emulator.Gleb Natapov
If VMX reports segment as unusable, zero descriptor passed by the emulator before returning. Such descriptor will be considered not present by the emulator. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-24KVM: VMX: rename fix_pmode_dataseg to fix_pmode_seg.Gleb Natapov
The function deals with code segment too. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-24KVM: VMX: don't clobber segment AR of unusable segments.Gleb Natapov
Usability is returned in unusable field, so not need to clobber entire AR. Callers have to know how to deal with unusable segments already since if emulate_invalid_guest_state=true AR is not zeroed. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-24KVM: VMX: skip vmx->rmode.vm86_active check on cr0 write if unrestricted ↵Gleb Natapov
guest is enabled vmx->rmode.vm86_active is never true is unrestricted guest is enabled. Make it more explicit that neither enter_pmode() nor enter_rmode() is called in this case. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-24KVM: VMX: remove hack that disables emulation on vcpu reset/initGleb Natapov
There is no reason for it. If state is suitable for vmentry it will be detected during guest entry and no emulation will happen. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-24KVM: VMX: if unrestricted guest is enabled vcpu state is always valid.Gleb Natapov
Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-24KVM: VMX: reset CPL only on CS register write.Gleb Natapov
Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-24KVM: VMX: remove special CPL cache access during transition to real mode.Gleb Natapov
Since vmx_get_cpl() always returns 0 when VCPU is in real mode it is no longer needed. Also reset CPL cache to zero during transaction to protected mode since transaction may happen while CS.selectors & 3 != 0, but in reality CPL is 0. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-23KVM: x86 emulator: convert a few freestanding emulations to fastopAvi Kivity
Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi.kivity@gmail.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-23KVM: x86 emulator: rearrange fastop definitionsAvi Kivity
Make fastop opcodes usable in other emulations. Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi.kivity@gmail.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-23KVM: x86 emulator: convert 2-operand IMUL to fastopAvi Kivity
Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi.kivity@gmail.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-23KVM: x86 emulator: convert BT/BTS/BTR/BTC/BSF/BSR to fastopAvi Kivity
Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi.kivity@gmail.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-23KVM: x86 emulator: convert INC/DEC to fastopAvi Kivity
Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi.kivity@gmail.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-23KVM: x86 emulator: covert SETCC to fastopAvi Kivity
This is a bit of a special case since we don't have the usual byte/word/long/quad switch; instead we switch on the condition code embedded in the instruction. Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi.kivity@gmail.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-23KVM: x86 emulator: convert shift/rotate instructions to fastopAvi Kivity
SHL, SHR, ROL, ROR, RCL, RCR, SAR, SAL Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi.kivity@gmail.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-23KVM: x86 emulator: Convert SHLD, SHRD to fastopAvi Kivity
Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi.kivity@gmail.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-21KVM: x86: improve reexecute_instructionXiao Guangrong
The current reexecute_instruction can not well detect the failed instruction emulation. It allows guest to retry all the instructions except it accesses on error pfn For example, some cases are nested-write-protect - if the page we want to write is used as PDE but it chains to itself. Under this case, we should stop the emulation and report the case to userspace Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-21KVM: x86: let reexecute_instruction work for tdpXiao Guangrong
Currently, reexecute_instruction refused to retry all instructions if tdp is enabled. If nested npt is used, the emulation may be caused by shadow page, it can be fixed by dropping the shadow page. And the only condition that tdp can not retry the instruction is the access fault on error pfn Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-21KVM: x86: clean up reexecute_instructionXiao Guangrong
Little cleanup for reexecute_instruction, also use gpa_to_gfn in retry_instruction Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-01-14KVM: MMU: Conditionally reschedule when kvm_mmu_slot_remove_write_access() ↵Takuya Yoshikawa
takes a long time If the userspace starts dirty logging for a large slot, say 64GB of memory, kvm_mmu_slot_remove_write_access() needs to hold mmu_lock for a long time such as tens of milliseconds. This patch controls the lock hold time by asking the scheduler if we need to reschedule for others. One penalty for this is that we need to flush TLBs before releasing mmu_lock. But since holding mmu_lock for a long time does affect not only the guest, vCPU threads in other words, but also the host as a whole, we should pay for that. In practice, the cost will not be so high because we can protect a fair amount of memory before being rescheduled: on my test environment, cond_resched_lock() was called only once for protecting 12GB of memory even without THP. We can also revisit Avi's "unlocked TLB flush" work later for completely suppressing extra TLB flushes if needed. Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Gleb Natapov <gleb@redhat.com>
2013-01-14KVM: Make kvm_mmu_slot_remove_write_access() take mmu_lock by itselfTakuya Yoshikawa
Better to place mmu_lock handling and TLB flushing code together since this is a self-contained function. Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Gleb Natapov <gleb@redhat.com>
2013-01-14KVM: Make kvm_mmu_change_mmu_pages() take mmu_lock by itselfTakuya Yoshikawa
No reason to make callers take mmu_lock since we do not need to protect kvm_mmu_change_mmu_pages() and kvm_mmu_slot_remove_write_access() together by mmu_lock in kvm_arch_commit_memory_region(): the former calls kvm_mmu_commit_zap_page() and flushes TLBs by itself. Note: we do not need to protect kvm->arch.n_requested_mmu_pages by mmu_lock as can be seen from the fact that it is read locklessly. Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Gleb Natapov <gleb@redhat.com>
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