- 10 Jul, 2020 14 commits
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Vitaly Kuznetsov authored
Make nSVM code resemble nVMX where nested_vmx_load_cr3() is used on both guest->host and host->guest transitions. Also, we can now eliminate unconditional kvm_mmu_reset_context() and speed things up. Note, nVMX has two different paths: load_vmcs12_host_state() and nested_vmx_restore_host_state() and the later is used to restore from 'partial' switch to L2, it always uses kvm_mmu_reset_context(). nSVM doesn't have this yet. Also, nested_svm_vmexit()'s return value is almost always ignored nowadays. Signed-off-by:
Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20200710141157.1640173-9-vkuznets@redhat.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Vitaly Kuznetsov authored
Undesired triple fault gets injected to L1 guest on SVM when L2 is launched with certain CR3 values. #TF is raised by mmu_check_root() check in fast_pgd_switch() and the root cause is that when kvm_set_cr3() is called from nested_prepare_vmcb_save() with NPT enabled CR3 points to a nGPA so we can't check it with kvm_is_visible_gfn(). Using generic kvm_set_cr3() when switching to nested guest is not a great idea as we'll have to distinguish between 'real' CR3s and 'nested' CR3s to e.g. not call kvm_mmu_new_pgd() with nGPA. Following nVMX implement nested-specific nested_svm_load_cr3() doing the job. To support the change, nested_svm_load_cr3() needs to be re-ordered with nested_svm_init_mmu_context(). Note: the current implementation is sub-optimal as we always do TLB flush/MMU sync but this is still an improvement as we at least stop doing kvm_mmu_reset_context(). Fixes: 7c390d35 ("kvm: x86: Add fast CR3 switch code path") Signed-off-by:
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Vitaly Kuznetsov authored
kvm_mmu_new_pgd() refers to arch.mmu and at this point it still references arch.guest_mmu while arch.root_mmu is expected. Note, the change is effectively a nop: when !npt_enabled, nested_svm_uninit_mmu_context() does nothing (as we don't do nested_svm_init_mmu_context()) and with npt_enabled we don't do kvm_set_cr3(). However, it will matter when we move the call to kvm_mmu_new_pgd into nested_svm_load_cr3(). No functional change intended. Signed-off-by:
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Vitaly Kuznetsov authored
As a preparatory change for implementing nSVM-specific PGD switch (following nVMX' nested_vmx_load_cr3()), introduce nested_svm_load_cr3() instead of relying on kvm_set_cr3(). No functional change intended. Signed-off-by:
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Vitaly Kuznetsov authored
Some operations in enter_svm_guest_mode() may fail, e.g. currently we suppress kvm_set_cr3() return value. Prepare the code to proparate errors. No functional change intended. Signed-off-by:
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Vitaly Kuznetsov authored
WARN_ON_ONCE(svm->nested.nested_run_pending) in nested_svm_vmexit() will fire if nested_run_pending remains '1' but it doesn't really need to, we are already failing and not going to run nested guest. Signed-off-by:
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Paolo Bonzini authored
kvm_init_shadow_mmu() was actually the only function that could be called with different vcpu->arch.mmu values. Now that kvm_init_shadow_npt_mmu() is separated from kvm_init_shadow_mmu(), we always know the MMU context we need to use and there is no need to dereference vcpu->arch.mmu pointer. Based on a patch by Vitaly Kuznetsov <vkuznets@redhat.com>. Signed-off-by:
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Vitaly Kuznetsov authored
As a preparatory change for moving kvm_mmu_new_pgd() from nested_prepare_vmcb_save() to nested_svm_init_mmu_context() split kvm_init_shadow_npt_mmu() from kvm_init_shadow_mmu(). This also makes the code look more like nVMX (kvm_init_shadow_ept_mmu()). No functional change intended. Signed-off-by:
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Vitaly Kuznetsov authored
state_test/smm_test selftests are failing on AMD with: "Unexpected result from KVM_GET_MSRS, r: 51 (failed MSR was 0x345)" MSR_IA32_PERF_CAPABILITIES is an emulated MSR on Intel but it is not known to AMD code, we can move the emulation to common x86 code. For AMD, we basically just allow the host to read and write zero to the MSR. Fixes: 27461da3 ("KVM: x86/pmu: Support full width counting") Suggested-by:
Jim Mattson <jmattson@google.com> Suggested-by:
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Tianjia Zhang authored
In the current kvm version, 'kvm_run' has been included in the 'kvm_vcpu' structure. For historical reasons, many kvm-related function parameters retain the 'kvm_run' and 'kvm_vcpu' parameters at the same time. This patch does a unified cleanup of these remaining redundant parameters. Signed-off-by:
Tianjia Zhang <tianjia.zhang@linux.alibaba.com> Reviewed-by:
Huacai Chen <chenhc@lemote.com> Message-Id: <20200623131418.31473-5-tianjia.zhang@linux.alibaba.com> Signed-off-by:
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Tianjia Zhang authored
In the current kvm version, 'kvm_run' has been included in the 'kvm_vcpu' structure. For historical reasons, many kvm-related function parameters retain the 'kvm_run' and 'kvm_vcpu' parameters at the same time. This patch does a unified cleanup of these remaining redundant parameters. Signed-off-by:
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Tianjia Zhang authored
In the current kvm version, 'kvm_run' has been included in the 'kvm_vcpu' structure. For historical reasons, many kvm-related function parameters retain the 'kvm_run' and 'kvm_vcpu' parameters at the same time. This patch does a unified cleanup of these remaining redundant parameters. Signed-off-by:
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Jiaxun Yang authored
This file was created long ago and information inside is obviously outdated. Signed-off-by:
Jiaxun Yang <jiaxun.yang@flygoat.com> Message-Id: <20200710063047.154611-4-jiaxun.yang@flygoat.com> Signed-off-by:
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Jiaxun Yang authored
After tons of fixes to get Trap-and-Emulate build on Loongson64, I've got panic on host machine when trying to run a VM. I found that it can never work on 64bit systems. Revewing the code, it looks like R6 can't supportrd by TE as well. Signed-off-by:
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- 09 Jul, 2020 26 commits
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Sean Christopherson authored
Move to the common MMU memory cache implementation now that the common code and MIPS's existing code are semantically compatible. No functional change intended. Suggested-by:
Christoffer Dall <christoffer.dall@arm.com> Signed-off-by:
Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200703023545.8771-22-sean.j.christopherson@intel.com> Signed-off-by:
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Sean Christopherson authored
Use GFP_KERNEL_ACCOUNT instead of GFP_KERNEL when allocating pages for the the GPA page tables. The primary motivation for accounting the allocations is to align with the common KVM memory cache helpers in preparation for moving to the common implementation in a future patch. The actual accounting is a bonus side effect. Signed-off-by:
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Sean Christopherson authored
Replace the @max param in mmu_topup_memory_cache() and instead use ARRAY_SIZE() to terminate the loop to fill the cache. This removes a BUG_ON() and sets the stage for moving MIPS to the common memory cache implementation. No functional change intended. Signed-off-by:
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Sean Christopherson authored
Move to the common MMU memory cache implementation now that the common code and arm64's existing code are semantically compatible. No functional change intended. Cc: Marc Zyngier <maz@kernel.org> Suggested-by:
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Sean Christopherson authored
Add a "gfp_zero" member to arm64's 'struct kvm_mmu_memory_cache' to make the struct and its usage compatible with the common 'struct kvm_mmu_memory_cache' in linux/kvm_host.h. This will minimize code churn when arm64 moves to the common implementation in a future patch, at the cost of temporarily having somewhat silly code. Note, GFP_PGTABLE_USER is equivalent to GFP_KERNEL_ACCOUNT | GFP_ZERO: #define GFP_PGTABLE_USER (GFP_PGTABLE_KERNEL | __GFP_ACCOUNT) | -> #define GFP_PGTABLE_KERNEL (GFP_KERNEL | __GFP_ZERO) == GFP_KERNEL | __GFP_ACCOUNT | __GFP_ZERO versus #define GFP_KERNEL_ACCOUNT (GFP_KERNEL | __GFP_ACCOUNT) with __GFP_ZERO explicitly OR'd in == GFP_KERNEL | __GFP_ACCOUNT | __GFP_ZERO No functional change intended. Tested-by:Marc Zyngier <maz@kernel.org> Signed-off-by:
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Sean Christopherson authored
Replace the @max param in mmu_topup_memory_cache() and instead use ARRAY_SIZE() to terminate the loop to fill the cache. This removes a BUG_ON() and sets the stage for moving arm64 to the common memory cache implementation. No functional change intended. Tested-by:
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Sean Christopherson authored
Move x86's memory cache helpers to common KVM code so that they can be reused by arm64 and MIPS in future patches. Suggested-by:
Ben Gardon <bgardon@google.com> Signed-off-by:
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Sean Christopherson authored
Move x86's 'struct kvm_mmu_memory_cache' to common code in anticipation of moving the entire x86 implementation code to common KVM and reusing it for arm64 and MIPS. Add a new architecture specific asm/kvm_types.h to control the existence and parameters of the struct. The new header is needed to avoid a chicken-and-egg problem with asm/kvm_host.h as all architectures define instances of the struct in their vCPU structs. Add an asm-generic version of kvm_types.h to avoid having empty files on PPC and s390 in the long term, and for arm64 and mips in the short term. Suggested-by:
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Sean Christopherson authored
Rename the memory helpers that will soon be moved to common code and be made globaly available via linux/kvm_host.h. "mmu" alone is not a sufficient namespace for globally available KVM symbols. Opportunistically add "nr_" in mmu_memory_cache_free_objects() to make it clear the function returns the number of free objects, as opposed to freeing existing objects. Suggested-by:
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Sean Christopherson authored
Don't bother filling the gfn array cache when the caller is a fully direct MMU, i.e. won't need a gfn array for shadow pages. Reviewed-by:
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Sean Christopherson authored
Set __GFP_ZERO for the shadow page memory cache and drop the explicit clear_page() from kvm_mmu_get_page(). This moves the cost of zeroing a page to the allocation time of the physical page, i.e. when topping up the memory caches, and thus avoids having to zero out an entire page while holding mmu_lock. Cc: Peter Feiner <pfeiner@google.com> Cc: Peter Shier <pshier@google.com> Cc: Junaid Shahid <junaids@google.com> Cc: Jim Mattson <jmattson@google.com> Suggested-by:
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Sean Christopherson authored
Add a gfp_zero flag to 'struct kvm_mmu_memory_cache' and use it to control __GFP_ZERO instead of hardcoding a call to kmem_cache_zalloc(). A future patch needs such a flag for the __get_free_page() path, as gfn arrays do not need/want the allocator to zero the memory. Convert the kmem_cache paths to __GFP_ZERO now so as to avoid a weird and inconsistent API in the future. No functional change intended. Reviewed-by:
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Sean Christopherson authored
Use separate caches for allocating shadow pages versus gfn arrays. This sets the stage for specifying __GFP_ZERO when allocating shadow pages without incurring extra cost for gfn arrays. No functional change intended. Reviewed-by:
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Sean Christopherson authored
Clean up the minimums in mmu_topup_memory_caches() to document the driving mechanisms behind the minimums. Now that encountering an empty cache is unlikely to trigger BUG_ON(), it is less dangerous to be more precise when defining the minimums. For rmaps, the logic is 1 parent PTE per level, plus a single rmap, and prefetched rmaps. The extra objects in the current '8 + PREFETCH' minimum came about due to an abundance of paranoia in commit c41ef344 ("KVM: MMU: increase per-vcpu rmap cache alloc size"), i.e. it could have increased the minimum to 2 rmaps. Furthermore, the unexpected extra rmap case was killed off entirely by commits f759e2b4 ("KVM: MMU: avoid pte_list_desc running out in kvm_mmu_pte_write") and f5a1e9f8 ("KVM: MMU: remove call to kvm_mmu_pte_write from walk_addr"). For the so called page cache, replace '8' with 2*PT64_ROOT_MAX_LEVEL. The 2x multiplier is needed because the cache is used for both shadow pages and gfn arrays for indirect MMUs. And finally, for page headers, replace '4' with PT64_ROOT_MAX_LEVEL. Note, KVM now supports 5-level paging, i.e. the old minimums that used a baseline derived from 4-level paging were technically wrong. But, KVM always allocates roots in a separate flow, e.g. it's impossible in the current implementation to actually need 5 new shadow pages in a single flow. Use PT64_ROOT_MAX_LEVEL unmodified instead of subtracting 1, as the direct usage is likely more intuitive to uninformed readers, and the inflated minimum is unlikely to affect functionality in practice. Reviewed-by:
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Sean Christopherson authored
Topup memory caches after walking the GVA->GPA translation during a shadow page fault, there is no need to ensure the caches are full when walking the GVA. As of commit f5a1e9f8 ("KVM: MMU: remove call to kvm_mmu_pte_write from walk_addr"), the FNAME(walk_addr) flow no longer add rmaps via kvm_mmu_pte_write(). This avoids allocating memory in the case that the GVA is unmapped in the guest, and also provides a paper trail of why/when the memory caches need to be filled. Reviewed-by:
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Sean Christopherson authored
Avoid refilling the memory caches and potentially slow reclaim/swap when handling a fast page fault, which does not need to allocate any new objects. Reviewed-by:
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Sean Christopherson authored
Attempt to allocate a new object instead of crashing KVM (and likely the kernel) if a memory cache is unexpectedly empty. Use GFP_ATOMIC for the allocation as the caches are used while holding mmu_lock. The immediate BUG_ON() makes the code unnecessarily explosive and led to confusing minimums being used in the past, e.g. allocating 4 objects where 1 would suffice. Reviewed-by:
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Sean Christopherson authored
Return errors directly from mmu_topup_memory_caches() instead of branching to a label that does the same. No functional change intended. Reviewed-by:
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Sean Christopherson authored
Use "mc" for local variables to shorten line lengths and provide consistent names, which will be especially helpful when some of the helpers are moved to common KVM code in future patches. No functional change intended. Reviewed-by:
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Sean Christopherson authored
Drop the "page" variants of the topup/free memory cache helpers, using the existence of an associated kmem_cache to select the correct alloc or free routine. No functional change intended. Reviewed-by:
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Sean Christopherson authored
Track the kmem_cache used for non-page KVM MMU memory caches instead of passing in the associated kmem_cache when filling the cache. This will allow consolidating code and other cleanups. No functional change intended. Reviewed-by:
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Thomas Gleixner authored
read/write_cr2() go throuh the paravirt XXL indirection, but nested VMX in a XEN_PV guest is not supported. Use the native variants. Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Message-Id: <20200708195322.344731916@linutronix.de> Signed-off-by:
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Thomas Gleixner authored
On guest exit MSR_GS_BASE contains whatever the guest wrote to it and the first action after returning from the ASM code is to set it to the host kernel value. This uses wrmsrl() which is interesting at least. wrmsrl() is either using native_write_msr() or the paravirt variant. The XEN_PV code is uninteresting as nested SVM in a XEN_PV guest does not work. But native_write_msr() can be placed out of line by the compiler especially when paravirtualization is enabled in the kernel configuration. The function is marked notrace, but still can be probed if CONFIG_KPROBE_EVENTS_ON_NOTRACE is enabled. That would be a fatal problem as kprobe events use per-CPU variables which are GS based and would be accessed with the guest GS. Depending on the GS value this would either explode in colorful ways or lead to completely undebugable data corruption. Aside of that native_write_msr() contains a tracepoint which objtool complains about as it is invoked from the noinstr section. As this cannot run inside a XEN_PV guest there is no point in using wrmsrl(). Use native_wrmsrl() instead which is just a plain native WRMSR without tracing or anything else attached. Signed-off-by:
Juergen Gross <jgross@suse.com> Message-Id: <20200708195322.244847377@linutronix.de> Signed-off-by:
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Thomas Gleixner authored
Move the functions which are inside the RCU off region into the non-instrumentable text section. Signed-off-by:
Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by:
Peter Zijlstra <peterz@infradead.org> Acked-by:
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Thomas Gleixner authored
Move the functions which are inside the RCU off region into the non-instrumentable text section. Signed-off-by:
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Thomas Gleixner authored
Entering guest mode is more or less the same as returning to user space. From an instrumentation point of view both leave kernel mode and the transition to guest or user mode reenables interrupts on the host. In user mode an interrupt is served directly and in guest mode it causes a VM exit which then handles or reinjects the interrupt. The transition from guest mode or user mode to kernel mode disables interrupts, which needs to be recorded in instrumentation to set the correct state again. This is important for e.g. latency analysis because otherwise the execution time in guest or user mode would be wrongly accounted as interrupt disabled and could trigger false positives. Add hardirq tracing to guest enter/exit functions in the same way as it is done in the user mode enter/exit code, respecting the RCU requirements. Signed-off-by:
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