- 17 Mar, 2023 11 commits
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Lai Jiangshan authored
Rework "struct pte_list_desc" and pte_list_{add|remove} to track the tail count, i.e. number of PTEs in non-head descriptors, and to always keep all tail descriptors full so that adding a new entry and counting the number of entries is done in constant time instead of linear time. No visible performace is changed in tests. But pte_list_add() is no longer shown in the perf result for the COWed pages even the guest forks millions of tasks. Signed-off-by:Lai Jiangshan <jiangshan.ljs@antgroup.com> Link: https://lore.kernel.org/r/20230113122910.672417-1-jiangshanlai@gmail.com [sean: reword shortlog, tweak changelog, add lots of comments, add BUG_ON()] Signed-off-by:
Sean Christopherson <seanjc@google.com>
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Lai Jiangshan authored
Sync the spte only when the spte is set and avoid the indirect branch. Signed-off-by:
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Lai Jiangshan authored
FNAME(prefetch_gpte) is always called with @no_dirty_log=true. Signed-off-by:
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Lai Jiangshan authored
In hardware TLB, invalidating TLB entries means the translations are removed from the TLB. In KVM shadowed vTLB, the translations (combinations of shadow paging and hardware TLB) are generally maintained as long as they remain "clean" when the TLB of an address space (i.e. a PCID or all) is flushed with the help of write-protections, sp->unsync, and kvm_sync_page(), where "clean" in this context means that no updates to KVM's SPTEs are needed. However, FNAME(invlpg) always zaps/removes the vTLB if the shadow page is unsync, and thus triggers a remote flush even if the original vTLB entry is clean, i.e. is usable as-is. Besides this, FNAME(invlpg) is largely is a duplicate implementation of FNAME(sync_spte) to invalidate a vTLB entry. To address both issues, reuse FNAME(sync_spte) to share the code and slightly modify the semantics, i.e. keep the vTLB entry if it's "clean" and avoid remote TLB flush. Signed-off-by:
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Lai Jiangshan authored
Don't assume the current root to be valid, just check it and remove the WARN(). Also move the code to check if the root is valid into FNAME(invlpg) to simplify the code. Signed-off-by:
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Lai Jiangshan authored
Use kvm_mmu_invalidate_addr() instead open calls to mmu->invlpg(). No functional change intended. Signed-off-by:
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Lai Jiangshan authored
Use kvm_mmu_invalidate_addr() instead open calls to mmu->invlpg(). No functional change intended. Signed-off-by:
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Lai Jiangshan authored
The @root_hpa for kvm_mmu_invalidate_addr() is called with @mmu->root.hpa or INVALID_PAGE where @mmu->root.hpa is to invalidate gva for the current root (the same meaning as KVM_MMU_ROOT_CURRENT) and INVALID_PAGE is to invalidate gva for all roots (the same meaning as KVM_MMU_ROOTS_ALL). Change the argument type of kvm_mmu_invalidate_addr() and use KVM_MMU_ROOT_XXX instead so that we can reuse the function for kvm_mmu_invpcid_gva() and nested_ept_invalidate_addr() for invalidating gva for different set of roots. No fuctionalities changed. Signed-off-by:
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Sean Christopherson authored
Tweak KVM_MMU_ROOTS_ALL to precisely cover all current+previous root flags, and add a sanity in kvm_mmu_free_roots() to verify that the set of roots to free doesn't stray outside KVM_MMU_ROOTS_ALL. Signed-off-by:
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Lai Jiangshan authored
Sometimes when the guest updates its pagetable, it adds only new gptes to it without changing any existed one, so there is no point to update the sptes for these existed gptes. Also when the sptes for these unchanged gptes are updated, the AD bits are also removed since make_spte() is called with prefetch=true which might result unneeded TLB flushing. Just do nothing if the gpte's permissions are unchanged. Signed-off-by:
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Lai Jiangshan authored
Rename mmu->sync_page to mmu->sync_spte and move the code out of FNAME(sync_page)'s loop body into mmu.c. No functionalities change intended. Signed-off-by:
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- 16 Mar, 2023 13 commits
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Lai Jiangshan authored
mmu->sync_page for direct paging is never called. And both mmu->sync_page and mm->invlpg only make sense in shadow paging. Setting mmu->sync_page as NULL for direct paging makes it consistent with mm->invlpg which is set NULL for the case. Signed-off-by:
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Lai Jiangshan authored
Assert that mmu->sync_page is non-NULL as part of the sanity checks performed before attempting to sync a shadow page. Explicitly checking mmu->sync_page is all but guaranteed to be redundant with the existing sanity check that the MMU is indirect, but the cost is negligible, and the explicit check also serves as documentation. Signed-off-by:
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Lai Jiangshan authored
Prepare to check mmu->sync_page pointer before calling it. Signed-off-by:
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Lai Jiangshan authored
FNAME(invlpg)() and kvm_mmu_invalidate_gva() take a gva_t, i.e. unsigned long, as the type of the address to invalidate. On 32-bit kernels, the upper 32 bits of the GPA will get dropped when an L2 GPA address is invalidated in the shadowed nested TDP MMU. Convert it to u64 to fix the problem. Reported-by:
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Thomas Huth authored
All kvm_arch_vm_ioctl() implementations now only deal with "int" types as return values, so we can change the return type of these functions to use "int" instead of "long". Signed-off-by:
Thomas Huth <thuth@redhat.com> Acked-by:
Anup Patel <anup@brainfault.org> Message-Id: <20230208140105.655814-7-thuth@redhat.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Thomas Huth authored
KVM functions use "long" return values for functions that are wired up to "struct file_operations", but otherwise use "int" return values for functions that can return 0/-errno in order to avoid unintentional divergences between 32-bit and 64-bit kernels. Some code still uses "long" in unnecessary spots, though, which can cause a little bit of confusion and unnecessary size casts. Let's change these spots to use "int" types, too. Signed-off-by:
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Thomas Huth authored
In case of success, this function returns the amount of handled bytes. However, this does not work for large values: The function is called from kvm_arch_vm_ioctl() (which still returns a long), which in turn is called from kvm_vm_ioctl() in virt/kvm/kvm_main.c. And that function stores the return value in an "int r" variable. So the upper 32-bits of the "long" return value are lost there. KVM ioctl functions should only return "int" values, so let's limit the amount of bytes that can be requested here to INT_MAX to avoid the problem with the truncated return value. We can then also change the return type of the function to "int" to make it clearer that it is not possible to return a "long" here. Fixes: f0376edb ("KVM: arm64: Add ioctl to fetch/store tags in a guest") Signed-off-by:
Cornelia Huck <cohuck@redhat.com> Reviewed-by:
Gavin Shan <gshan@redhat.com> Reviewed-by:
Steven Price <steven.price@arm.com> Message-Id: <20230208140105.655814-5-thuth@redhat.com> Signed-off-by:
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Thomas Huth authored
The KVM_GET_NR_MMU_PAGES ioctl is quite questionable on 64-bit hosts since it fails to return the full 64 bits of the value that can be set with the corresponding KVM_SET_NR_MMU_PAGES call. Its "long" return value is truncated into an "int" in the kvm_arch_vm_ioctl() function. Since this ioctl also never has been used by userspace applications (QEMU, Google's internal VMM, kvmtool and CrosVM have been checked), it's likely the best if we remove this badly designed ioctl before anybody really tries to use it. Signed-off-by:
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Thomas Huth authored
These two functions only return normal integers, so it does not make sense to declare the return type as "long" here. Reviewed-by:
Claudio Imbrenda <imbrenda@linux.ibm.com> Signed-off-by:
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Thomas Huth authored
Most functions that are related to kvm_arch_vm_ioctl() already use "int" as return type to pass error values back to the caller. Some outlier functions use "long" instead for no good reason (they do not really require long values here). Let's standardize on "int" here to avoid casting the values back and forth between the two types. Reviewed-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
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Emanuele Giuseppe Esposito authored
FLUSH_L1D was already added in 11e34e64, but the feature is not visible to userspace yet. The bit definition: CPUID.(EAX=7,ECX=0):EDX[bit 28] If the feature is supported by the host, kvm should support it too so that userspace can choose whether to expose it to the guest or not. One disadvantage of not exposing it is that the guest will report a non existing vulnerability in /sys/devices/system/cpu/vulnerabilities/mmio_stale_data because the mitigation is present only if the guest supports (FLUSH_L1D and MD_CLEAR) or FB_CLEAR. Signed-off-by:
Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-Id: <20230201132905.549148-4-eesposit@redhat.com> Signed-off-by:
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Emanuele Giuseppe Esposito authored
Expose IA32_FLUSH_CMD to the guest if the guest CPUID enumerates support for this MSR. As with IA32_PRED_CMD, permission for unintercepted writes to this MSR will be granted to the guest after the first non-zero write. Signed-off-by:
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Emanuele Giuseppe Esposito authored
Expose IA32_FLUSH_CMD to the guest if the guest CPUID enumerates support for this MSR. As with IA32_PRED_CMD, permission for unintercepted writes to this MSR will be granted to the guest after the first non-zero write. Co-developed-by:
Jim Mattson <jmattson@google.com> Signed-off-by:
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- 14 Mar, 2023 16 commits
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Sean Christopherson authored
Rename enable_evmcs to __kvm_is_using_evmcs to match its wrapper, and to avoid confusion with enabling eVMCS for nested virtualization, i.e. have "enable eVMCS" be reserved for "enable eVMCS support for L1". No functional change intended. Signed-off-by:
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Sean Christopherson authored
Wrap enable_evmcs in a helper and stub it out when CONFIG_HYPERV=n in order to eliminate the static branch nop placeholders. clang-14 is clever enough to elide the nop, but gcc-12 is not. Stubbing out the key reduces the size of kvm-intel.ko by ~7.5% (200KiB) when compiled with gcc-12 (there are a _lot_ of VMCS accesses throughout KVM). Reviewed-by:
Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by:
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Sean Christopherson authored
Move the macros that define the set of VMCS controls that are supported by eVMCS1 from hyperv.h to hyperv.c, i.e. make them "private". The macros should never be consumed directly by KVM at-large since the "final" set of supported controls depends on guest CPUID. No functional change intended. Reviewed-by:
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Lai Jiangshan authored
Drop FNAME(is_self_change_mapping) and instead rely on kvm_mmu_hugepage_adjust() to adjust the hugepage accordingly. Prior to commit 4cd071d1 ("KVM: x86/mmu: Move calls to thp_adjust() down a level"), the hugepage adjustment was done before allocating new shadow pages, i.e. failed to restrict the hugepage sizes if a new shadow page resulted in account_shadowed() changing the disallowed hugepage tracking. Removing FNAME(is_self_change_mapping) fixes a bug reported by Huang Hang where KVM unnecessarily forces a 4KiB page. FNAME(is_self_change_mapping) has a defect in that it blindly disables _all_ hugepage mappings rather than trying to reduce the size of the hugepage. If the guest is writing to a 1GiB page and the 1GiB is self-referential but a 2MiB page is not, then KVM can and should create a 2MiB mapping. Add a comment above the call to kvm_mmu_hugepage_adjust() to call out the new dependency on adjusting the hugepage size after walking indirect PTEs. Reported-by:
Huang Hang <hhuang@linux.alibaba.com> Signed-off-by:
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Lai Jiangshan authored
Move the detection of write #PF to shadow pages, i.e. a fault on a write to a page table that is being shadowed by KVM that is used to translate the write itself, from FNAME(is_self_change_mapping) to FNAME(fetch). There is no need to detect the self-referential write before kvm_faultin_pfn() as KVM does not consume EMULTYPE_WRITE_PF_TO_SP for accesses that resolve to "error or no-slot" pfns, i.e. KVM doesn't allow retrying MMIO accesses or writes to read-only memslots. Detecting the EMULTYPE_WRITE_PF_TO_SP scenario in FNAME(fetch) will allow dropping FNAME(is_self_change_mapping) entirely, as the hugepage interaction can be deferred to kvm_mmu_hugepage_adjust(). Cc: Huang Hang <hhuang@linux.alibaba.com> Signed-off-by:
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Sean Christopherson authored
Use a new EMULTYPE flag, EMULTYPE_WRITE_PF_TO_SP, to track page faults on self-changing writes to shadowed page tables instead of propagating that information to the emulator via a semi-persistent vCPU flag. Using a flag in "struct kvm_vcpu_arch" is confusing, especially as implemented, as it's not at all obvious that clearing the flag only when emulation actually occurs is correct. E.g. if KVM sets the flag and then retries the fault without ever getting to the emulator, the flag will be left set for future calls into the emulator. But because the flag is consumed if and only if both EMULTYPE_PF and EMULTYPE_ALLOW_RETRY_PF are set, and because EMULTYPE_ALLOW_RETRY_PF is deliberately not set for direct MMUs, emulated MMIO, or while L2 is active, KVM avoids false positives on a stale flag since FNAME(page_fault) is guaranteed to be run and refresh the flag before it's ultimately consumed by the tail end of reexecute_instruction(). Signed-off-by:
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Vipin Sharma authored
Add missing KVM_EXIT_* reasons in KVM selftests from include/uapi/linux/kvm.h Signed-off-by:
Vipin Sharma <vipinsh@google.com> Message-Id: <20230204014547.583711-5-vipinsh@google.com> Signed-off-by:
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Sean Christopherson authored
Add and use a macro to generate the KVM exit reason strings array instead of relying on developers to correctly copy+paste+edit each string. Signed-off-by:
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Vipin Sharma authored
Print what KVM exit reason a test was expecting and what it actually got int TEST_ASSERT_KVM_EXIT_REASON(). Signed-off-by:
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Vipin Sharma authored
Make TEST_ASSERT_KVM_EXIT_REASON() macro and replace all exit reason test assert statements with it. No functional changes intended. Signed-off-by:
David Matlack <dmatlack@google.com> Message-Id: <20230204014547.583711-2-vipinsh@google.com> Signed-off-by:
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David Woodhouse authored
When kvm_xen_evtchn_send() takes the slow path because the shinfo GPC needs to be revalidated, it used to violate the SRCU vs. kvm->lock locking rules and potentially cause a deadlock. Now that lockdep is learning to catch such things, make sure that code path is exercised by the selftest. Link: https://lore.kernel.org/all/20230113124606.10221-2-dwmw2@infradead.orgSigned-off-by:
David Woodhouse <dwmw@amazon.co.uk> Signed-off-by:
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David Woodhouse authored
The xen_shinfo_test started off with very few iterations, and the numbers we used in GUEST_SYNC() were precisely mapped to the RUNSTATE_xxx values anyway to start with. It has since grown quite a few more tests, and it's kind of awful to be handling them all as bare numbers. Especially when I want to add a new test in the middle. Define an enum for the test stages, and use it both in the guest code and the host switch statement. No functional change, if I can count to 24. Signed-off-by:
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Sean Christopherson authored
Add wrappers to do hypercalls using VMCALL/VMMCALL and Xen's register ABI (as opposed to full Xen-style hypercalls through a hypervisor provided page). Using the common helpers dedups a pile of code, and uses the native hypercall instruction when running on AMD. Signed-off-by:
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Sean Christopherson authored
Extract the guts of kvm_hypercall() to a macro so that Xen hypercalls, which have a different register ABI, can reuse the VMCALL vs. VMMCALL logic. No functional change intended. Signed-off-by:
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Sean Christopherson authored
WARN if generating a GATag given a VM ID and vCPU ID doesn't yield the same IDs when pulling the IDs back out of the tag. Don't bother adding error handling to callers, this is very much a paranoid sanity check as KVM fully controls the VM ID and is supposed to reject too-big vCPU IDs. Signed-off-by:
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Tested-by:
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Suravee Suthikulpanit authored
Define AVIC_VCPU_ID_MASK based on AVIC_PHYSICAL_MAX_INDEX, i.e. the mask that effectively controls the largest guest physical APIC ID supported by x2AVIC, instead of hardcoding the number of bits to 8 (and the number of VM bits to 24). The AVIC GATag is programmed into the AMD IOMMU IRTE to provide a reference back to KVM in case the IOMMU cannot inject an interrupt into a non-running vCPU. In such a case, the IOMMU notifies software by creating a GALog entry with the corresponded GATag, and KVM then uses the GATag to find the correct VM+vCPU to kick. Dropping bit 8 from the GATag results in kicking the wrong vCPU when targeting vCPUs with x2APIC ID > 255. Fixes: 4d1d7942 ("KVM: SVM: Introduce logic to (de)activate x2AVIC mode") Cc: stable@vger.kernel.org Reported-by:
Alejandro Jimenez <alejandro.j.jimenez@oracle.com> Signed-off-by:
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