- Mar 17, 2020
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Sean Christopherson authored
Now that the memslot logic doesn't assume memslots are always non-NULL, dynamically size the array of memslots instead of unconditionally allocating memory for the maximum number of memslots. Note, because a to-be-deleted memslot must first be invalidated, the array size cannot be immediately reduced when deleting a memslot. However, consecutive deletions will realize the memory savings, i.e. a second deletion will trim the entry. Tested-by:
Christoffer Dall <christoffer.dall@arm.com> Tested-by:
Marc Zyngier <maz@kernel.org> Reviewed-by:
Peter Xu <peterx@redhat.com> Signed-off-by:
Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Sean Christopherson authored
Refactor memslot handling to treat the number of used slots as the de facto size of the memslot array, e.g. return NULL from id_to_memslot() when an invalid index is provided instead of relying on npages==0 to detect an invalid memslot. Rework the sorting and walking of memslots in advance of dynamically sizing memslots to aid bisection and debug, e.g. with luck, a bug in the refactoring will bisect here and/or hit a WARN instead of randomly corrupting memory. Alternatively, a global null/invalid memslot could be returned, i.e. so callers of id_to_memslot() don't have to explicitly check for a NULL memslot, but that approach runs the risk of introducing difficult-to- debug issues, e.g. if the global null slot is modified. Constifying the return from id_to_memslot() to combat such issues is possible, but would require a massive refactoring of arch specific code and would still be susceptible to casting shenanigans. Add function comments to update_memslots() and search_memslots() to explicitly (and loudly) state how memslots are sorted. Opportunistically stuff @hva with a non-canonical value when deleting a private memslot on x86 to detect bogus usage of the freed slot. No functional change intended. Tested-by:
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Sean Christopherson authored
Rework kvm_get_dirty_log() so that it "returns" the associated memslot on success. A future patch will rework memslot handling such that id_to_memslot() can return NULL, returning the memslot makes it more obvious that the validity of the memslot has been verified, i.e. precludes the need to add validity checks in the arch code that are technically unnecessary. To maintain ordering in s390, move the call to kvm_arch_sync_dirty_log() from s390's kvm_vm_ioctl_get_dirty_log() to the new kvm_get_dirty_log(). This is a nop for PPC, the only other arch that doesn't select KVM_GENERIC_DIRTYLOG_READ_PROTECT, as its sync_dirty_log() is empty. Ideally, moving the sync_dirty_log() call would be done in a separate patch, but it can't be done in a follow-on patch because that would temporarily break s390's ordering. Making the move in a preparatory patch would be functionally correct, but would create an odd scenario where the moved sync_dirty_log() would operate on a "different" memslot due to consuming the result of a different id_to_memslot(). The memslot couldn't actually be different as slots_lock is held, but the code is confusing enough as it is, i.e. moving sync_dirty_log() in this patch is the lesser of all evils. Signed-off-by:
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Sean Christopherson authored
Move the implementations of KVM_GET_DIRTY_LOG and KVM_CLEAR_DIRTY_LOG for CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT into common KVM code. The arch specific implemenations are extremely similar, differing only in whether the dirty log needs to be sync'd from hardware (x86) and how the TLBs are flushed. Add new arch hooks to handle sync and TLB flush; the sync will also be used for non-generic dirty log support in a future patch (s390). The ulterior motive for providing a common implementation is to eliminate the dependency between arch and common code with respect to the memslot referenced by the dirty log, i.e. to make it obvious in the code that the validity of the memslot is guaranteed, as a future patch will rework memslot handling such that id_to_memslot() can return NULL. Signed-off-by:
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Sean Christopherson authored
Clean up __kvm_set_memory_region() to achieve several goals: - Remove local variables that serve no real purpose - Improve the readability of the code - Better show the relationship between the 'old' and 'new' memslot - Prepare for dynamically sizing memslots - Document subtle gotchas (via comments) Note, using 'tmp' to hold the initial memslot is not strictly necessary at this juncture, e.g. 'old' could be directly copied from id_to_memslot(), but keep the pointer usage as id_to_memslot() will be able to return a NULL pointer once memslots are dynamically sized. Signed-off-by:
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Sean Christopherson authored
Now that all callers of kvm_free_memslot() pass NULL for @dont, remove the param from the top-level routine and all arch's implementations. No functional change intended. Tested-by:
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Sean Christopherson authored
Move memslot deletion into its own routine so that the success path for other memslot updates does not need to use kvm_free_memslot(), i.e. can explicitly destroy the dirty bitmap when necessary. This paves the way for dropping @dont from kvm_free_memslot(), i.e. all callers now pass NULL for @dont. Add a comment above the code to make a copy of the existing memslot prior to deletion, it is not at all obvious that the pointer will become stale during sorting and/or installation of new memslots. Note, kvm_arch_commit_memory_region() allows an architecture to free resources when moving a memslot or changing its flags, e.g. x86 frees its arch specific memslot metadata during commit_memory_region(). Acked-by:
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Sean Christopherson authored
Explicitly free the metadata arrays (stored in slot->arch) in the old memslot structure when moving the memslot's base gfn is committed. This eliminates x86's dependency on kvm_free_memslot() being called when a memslot move is committed, and paves the way for removing the funky code in kvm_free_memslot() that conditionally frees structures based on its @dont param. Reviewed-by:
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Sean Christopherson authored
Drop the "const" attribute from @old in kvm_arch_commit_memory_region() to allow arch specific code to free arch specific resources in the old memslot without having to cast away the attribute. Freeing resources in kvm_arch_commit_memory_region() paves the way for simplifying kvm_free_memslot() by eliminating the last usage of its @dont param. Reviewed-by:
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Sean Christopherson authored
Split out the core functionality of setting a memslot into a separate helper in preparation for moving memslot deletion into its own routine. Tested-by:
Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by:
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Sean Christopherson authored
Replace a big pile o' gotos with returns to make it more obvious what error code is being returned, and to prepare for refactoring the functional, i.e. post-checks, portion of __kvm_set_memory_region(). Reviewed-by:
Janosch Frank <frankja@linux.ibm.com> Reviewed-by:
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Sean Christopherson authored
Explicitly free an allocated-but-unused dirty bitmap instead of relying on kvm_free_memslot() if an error occurs in __kvm_set_memory_region(). There is no longer a need to abuse kvm_free_memslot() to free arch specific resources as arch specific code is now called only after the common flow is guaranteed to succeed. Arch code can still fail, but it's responsible for its own cleanup in that case. Eliminating the error path's abuse of kvm_free_memslot() paves the way for simplifying kvm_free_memslot(), i.e. dropping its @dont param. Reviewed-by:
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Sean Christopherson authored
Remove kvm_arch_create_memslot() now that all arch implementations are effectively nops. Removing kvm_arch_create_memslot() eliminates the possibility for arch specific code to allocate memory prior to setting a memslot, which sets the stage for simplifying kvm_free_memslot(). Cc: Janosch Frank <frankja@linux.ibm.com> Acked-by:
Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by:
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Sean Christopherson authored
Allocate the various metadata structures associated with a new memslot during kvm_arch_prepare_memory_region(), which paves the way for removing kvm_arch_create_memslot() altogether. Moving x86's memory allocation only changes the order of kernel memory allocations between x86 and common KVM code. Reviewed-by:
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Sean Christopherson authored
Allocate the rmap array during kvm_arch_prepare_memory_region() to pave the way for removing kvm_arch_create_memslot() altogether. Moving PPC's memory allocation only changes the order of kernel memory allocations between PPC and common KVM code. No functional change intended. Acked-by:
Paul Mackerras <paulus@ozlabs.org> Reviewed-by:
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Sean Christopherson authored
The two implementations of kvm_arch_create_memslot() in x86 and PPC are both good citizens and free up all local resources if creation fails. Return immediately (via a superfluous goto) instead of calling kvm_free_memslot(). Note, the call to kvm_free_memslot() is effectively an expensive nop in this case as there are no resources to be freed. No functional change intended. Acked-by:
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Sean Christopherson authored
Reinstall the old memslots if preparing the new memory region fails after invalidating a to-be-{re}moved memslot. Remove the superfluous 'old_memslots' variable so that it's somewhat clear that the error handling path needs to free the unused memslots, not simply the 'old' memslots. Fixes: bc6678a3 ("KVM: introduce kvm->srcu and convert kvm_set_memory_region to SRCU update") Reviewed-by: -
Sean Christopherson authored
Reallocate a rmap array and recalcuate large page compatibility when moving an existing memslot to correctly handle the alignment properties of the new memslot. The number of rmap entries required at each level is dependent on the alignment of the memslot's base gfn with respect to that level, e.g. moving a large-page aligned memslot so that it becomes unaligned will increase the number of rmap entries needed at the now unaligned level. Not updating the rmap array is the most obvious bug, as KVM accesses garbage data beyond the end of the rmap. KVM interprets the bad data as pointers, leading to non-canonical #GPs, unexpected #PFs, etc... general protection fault: 0000 [#1] SMP CPU: 0 PID: 1909 Comm: move_memory_reg Not tainted 5.4.0-rc7+ #139 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:rmap_get_first+0x37/0x50 [kvm] Code: <48> 8b 3b 48 85 ff 74 ec e8 6c f4 ff ff 85 c0 74 e3 48 89 d8 5b c3 RSP: 0018:ffffc9000021bbc8 EFLAGS: 00010246 RAX: ffff00617461642e RBX: ffff00617461642e RCX: 0000000000000012 RDX: ffff88827400f568 RSI: ffffc9000021bbe0 RDI: ffff88827400f570 RBP: 0010000000000000 R08: ffffc9000021bd00 R09: ffffc9000021bda8 R10: ffffc9000021bc48 R11: 0000000000000000 R12: 0030000000000000 R13: 0000000000000000 R14: ffff88827427d700 R15: ffffc9000021bce8 FS: 00007f7eda014700(0000) GS:ffff888277a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7ed9216ff8 CR3: 0000000274391003 CR4: 0000000000162eb0 Call Trace: kvm_mmu_slot_set_dirty+0xa1/0x150 [kvm] __kvm_set_memory_region.part.64+0x559/0x960 [kvm] kvm_set_memory_region+0x45/0x60 [kvm] kvm_vm_ioctl+0x30f/0x920 [kvm] do_vfs_ioctl+0xa1/0x620 ksys_ioctl+0x66/0x70 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x4c/0x170 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f7ed9911f47 Code: <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 21 6f 2c 00 f7 d8 64 89 01 48 RSP: 002b:00007ffc00937498 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000001ab0010 RCX: 00007f7ed9911f47 RDX: 0000000001ab1350 RSI: 000000004020ae46 RDI: 0000000000000004 RBP: 000000000000000a R08: 0000000000000000 R09: 00007f7ed9214700 R10: 00007f7ed92149d0 R11: 0000000000000246 R12: 00000000bffff000 R13: 0000000000000003 R14: 00007f7ed9215000 R15: 0000000000000000 Modules linked in: kvm_intel kvm irqbypass ---[ end trace 0c5f570b3358ca89 ]--- The disallow_lpage tracking is more subtle. Failure to update results in KVM creating large pages when it shouldn't, either due to stale data or again due to indexing beyond the end of the metadata arrays, which can lead to memory corruption and/or leaking data to guest/userspace. Note, the arrays for the old memslot are freed by the unconditional call to kvm_free_memslot() in __kvm_set_memory_region(). Fixes: 05da4558 ("KVM: MMU: large page support") Cc: stable@vger.kernel.org Signed-off-by:
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Sean Christopherson authored
Move the GPA tracking into the emulator context now that the context is guaranteed to be initialized via __init_emulate_ctxt() prior to dereferencing gpa_{available,val}, i.e. now that seeing a stale gpa_available will also trigger a WARN due to an invalid context. Signed-off-by: -
Sean Christopherson authored
Add a new emulation type flag to explicitly mark emulation related to a page fault. Move the propation of the GPA into the emulator from the page fault handler into x86_emulate_instruction, using EMULTYPE_PF as an indicator that cr2 is valid. Similarly, don't propagate cr2 into the exception.address when it's *not* valid. Signed-off-by:
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Miaohe Lin authored
The function apic_lvt_vector() is unused now, remove it. Signed-off-by:
Miaohe Lin <linmiaohe@huawei.com> Signed-off-by:
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Miaohe Lin authored
Each if branch in handle_external_interrupt_irqoff() is mutually exclusive. Add 'else' to make it clear and also avoid some unnecessary check. Signed-off-by:
Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by:
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Miaohe Lin authored
These code are unreachable, remove them. Signed-off-by:
Krish Sadhukhan <krish.sadhukhan@oracle.com> Reviewed-by:
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Miaohe Lin authored
Use %u to print u32 var and correct some coding style. Signed-off-by:
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Chia-I Wu authored
Better reflect the structure of the code and metion why we could not always honor the guest. Signed-off-by:
Chia-I Wu <olvaffe@gmail.com> Cc: Gurchetan Singh <gurchetansingh@chromium.org> Cc: Gerd Hoffmann <kraxel@redhat.com> Signed-off-by:
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Andrew Jones authored
We leave some printf's because they inform the user the test is being skipped. QUIET should not disable those. We also leave the printf's used for help text. Signed-off-by:
Andrew Jones <drjones@redhat.com> Signed-off-by:
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Andrew Jones authored
There were a few problems with the way we output "debug" messages. The first is that we used DEBUG() which is defined when NDEBUG is not defined, but NDEBUG will never be defined for kselftests because it relies too much on assert(). The next is that most of the DEBUG() messages were actually "info" messages, which users may want to turn off if they just want a silent test that either completes or asserts. Finally, a debug message output from a library function, and thus for all tests, was annoying when its information wasn't interesting for a test. Rework these messages so debug messages only output when DEBUG is defined and info messages output unless QUIET is defined. Also name the functions pr_debug and pr_info and make sure that when they're disabled we eat all the inputs. The later avoids unused variable warnings when the variables were only defined for the purpose of printing. Signed-off-by:
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Ben Gardon authored
In order to quantify demand paging performance, time guest execution during demand paging. Signed-off-by:
Ben Gardon <bgardon@google.com> [Move timespec-diff to test_util.h] Signed-off-by:
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Ben Gardon authored
Most VMs have multiple vCPUs, the concurrent execution of which has a substantial impact on demand paging performance. Add an option to create multiple vCPUs to each access disjoint regions of memory. Signed-off-by:
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Ben Gardon authored
Currently vcpu_args_set is only implemented for x86. This makes writing tests with multiple vCPUs difficult as each guest vCPU must either a.) do the same thing or b.) derive some kind of unique token from it's registers or the architecture. To simplify the process of writing tests with multiple vCPUs for s390 and aarch64, add set args functions for those architectures. Signed-off-by:
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Ben Gardon authored
In preparation for supporting multiple vCPUs in the demand paging test, pass arguments to the vCPU in a consolidated global struct instead of syncing multiple globals. Signed-off-by:
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Ben Gardon authored
Add an argument to allow the demand paging test to work on larger and smaller guest sizes. Signed-off-by:
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Ben Gardon authored
When running the demand paging test with the -u option, the User Fault FD handler essentially adds an arbitrary delay to page fault resolution. To enable better simulation of a real demand paging scenario, add a configurable delay to the UFFD handler. Reviewed-by:
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Ben Gardon authored
The demand paging test is currently a simple page access test which, while potentially useful, doesn't add much versus the existing dirty logging test. To improve the demand paging test, add a basic userfaultfd demand paging implementation. Signed-off-by:
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- Feb 25, 2020
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Ben Gardon authored
While userfaultfd, KVM's demand paging implementation, is not specific to KVM, having a benchmark for its performance will be useful for guiding performance improvements to KVM. As a first step towards creating a userfaultfd demand paging test, create a simple memory access test, based on dirty_log_test. Reviewed-by:
Oliver Upton <oupton@google.com> Signed-off-by:
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Andrew Jones authored
Guests and hosts don't have to have the same page size. This means calculations are necessary when selecting the number of guest pages to allocate in order to ensure the number is compatible with the host. Provide utilities to help with those calculations and apply them where appropriate. We also revert commit bffed38d ("kvm: selftests: aarch64: dirty_log_test: fix unaligned memslot size") and then use vm_adjust_num_guest_pages() there instead. Signed-off-by:
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Andrew Jones authored
This array will allow us to easily translate modes to their parameter values. Signed-off-by:
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Andrew Jones authored
We're going to want this name in the library code, so use a shorter name in the tests. Signed-off-by:
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Andrew Jones authored
Signed-off-by:
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Andrew Jones authored
BITS_PER_LONG and friends are provided by linux/bitops.h Signed-off-by:
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