diff options
Diffstat (limited to 'Documentation/virt')
| -rw-r--r-- | Documentation/virt/kvm/api.rst | 36 | ||||
| -rw-r--r-- | Documentation/virt/kvm/x86/mmu.rst | 43 |
2 files changed, 61 insertions, 18 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index edc682a94ca4..e81ab4e171e4 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -547,7 +547,7 @@ ioctl is useful if the in-kernel PIC is not used. PPC: ^^^^ -Queues an external interrupt to be injected. This ioctl is overleaded +Queues an external interrupt to be injected. This ioctl is overloaded with 3 different irq values: a) KVM_INTERRUPT_SET @@ -998,7 +998,7 @@ be set in the flags field of this ioctl: The KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL flag requests KVM to generate the contents of the hypercall page automatically; hypercalls will be intercepted and passed to userspace through KVM_EXIT_XEN. In this -ase, all of the blob size and address fields must be zero. +case, all of the blob size and address fields must be zero. The KVM_XEN_HVM_CONFIG_EVTCHN_SEND flag indicates to KVM that userspace will always use the KVM_XEN_HVM_EVTCHN_SEND ioctl to deliver event @@ -1103,7 +1103,7 @@ Other flags returned by ``KVM_GET_CLOCK`` are accepted but ignored. :Extended by: KVM_CAP_INTR_SHADOW :Architectures: x86, arm64 :Type: vcpu ioctl -:Parameters: struct kvm_vcpu_event (out) +:Parameters: struct kvm_vcpu_events (out) :Returns: 0 on success, -1 on error X86: @@ -1226,7 +1226,7 @@ directly to the virtual CPU). :Extended by: KVM_CAP_INTR_SHADOW :Architectures: x86, arm64 :Type: vcpu ioctl -:Parameters: struct kvm_vcpu_event (in) +:Parameters: struct kvm_vcpu_events (in) :Returns: 0 on success, -1 on error X86: @@ -3115,7 +3115,7 @@ as follow:: }; An entry with a "page_shift" of 0 is unused. Because the array is -organized in increasing order, a lookup can stop when encoutering +organized in increasing order, a lookup can stop when encountering such an entry. The "slb_enc" field provides the encoding to use in the SLB for the @@ -3507,7 +3507,7 @@ Possible features: - KVM_RUN and KVM_GET_REG_LIST are not available; - KVM_GET_ONE_REG and KVM_SET_ONE_REG cannot be used to access - the scalable archietctural SVE registers + the scalable architectural SVE registers KVM_REG_ARM64_SVE_ZREG(), KVM_REG_ARM64_SVE_PREG() or KVM_REG_ARM64_SVE_FFR; @@ -4453,7 +4453,7 @@ This will have undefined effects on the guest if it has not already placed itself in a quiescent state where no vcpu will make MMU enabled memory accesses. -On succsful completion, the pending HPT will become the guest's active +On successful completion, the pending HPT will become the guest's active HPT and the previous HPT will be discarded. On failure, the guest will still be operating on its previous HPT. @@ -5068,7 +5068,7 @@ before the vcpu is fully usable. Between KVM_ARM_VCPU_INIT and KVM_ARM_VCPU_FINALIZE, the feature may be configured by use of ioctls such as KVM_SET_ONE_REG. The exact configuration -that should be performaned and how to do it are feature-dependent. +that should be performed and how to do it are feature-dependent. Other calls that depend on a particular feature being finalized, such as KVM_RUN, KVM_GET_REG_LIST, KVM_GET_ONE_REG and KVM_SET_ONE_REG, will fail with @@ -5176,6 +5176,24 @@ Valid values for 'action':: #define KVM_PMU_EVENT_ALLOW 0 #define KVM_PMU_EVENT_DENY 1 +Via this API, KVM userspace can also control the behavior of the VM's fixed +counters (if any) by configuring the "action" and "fixed_counter_bitmap" fields. + +Specifically, KVM follows the following pseudo-code when determining whether to +allow the guest FixCtr[i] to count its pre-defined fixed event:: + + FixCtr[i]_is_allowed = (action == ALLOW) && (bitmap & BIT(i)) || + (action == DENY) && !(bitmap & BIT(i)); + FixCtr[i]_is_denied = !FixCtr[i]_is_allowed; + +KVM always consumes fixed_counter_bitmap, it's userspace's responsibility to +ensure fixed_counter_bitmap is set correctly, e.g. if userspace wants to define +a filter that only affects general purpose counters. + +Note, the "events" field also applies to fixed counters' hardcoded event_select +and unit_mask values. "fixed_counter_bitmap" has higher priority than "events" +if there is a contradiction between the two. + 4.121 KVM_PPC_SVM_OFF --------------------- @@ -5527,7 +5545,7 @@ KVM_XEN_ATTR_TYPE_EVTCHN from the guest. A given sending port number may be directed back to a specified vCPU (by APIC ID) / port / priority on the guest, or to trigger events on an eventfd. The vCPU and priority can be changed - by setting KVM_XEN_EVTCHN_UPDATE in a subsequent call, but but other + by setting KVM_XEN_EVTCHN_UPDATE in a subsequent call, but other fields cannot change for a given sending port. A port mapping is removed by using KVM_XEN_EVTCHN_DEASSIGN in the flags field. Passing KVM_XEN_EVTCHN_RESET in the flags field removes all interception of diff --git a/Documentation/virt/kvm/x86/mmu.rst b/Documentation/virt/kvm/x86/mmu.rst index d47595b33fcf..2b3b6d442302 100644 --- a/Documentation/virt/kvm/x86/mmu.rst +++ b/Documentation/virt/kvm/x86/mmu.rst @@ -202,10 +202,22 @@ Shadow pages contain the following information: Is 1 if the MMU instance cannot use A/D bits. EPT did not have A/D bits before Haswell; shadow EPT page tables also cannot use A/D bits if the L1 hypervisor does not enable them. + role.guest_mode: + Indicates the shadow page is created for a nested guest. role.passthrough: The page is not backed by a guest page table, but its first entry points to one. This is set if NPT uses 5-level page tables (host CR4.LA57=1) and is shadowing L1's 4-level NPT (L1 CR4.LA57=0). + mmu_valid_gen: + The MMU generation of this page, used to fast zap of all MMU pages within a + VM without blocking vCPUs too long. Specifically, KVM updates the per-VM + valid MMU generation which causes the mismatch of mmu_valid_gen for each mmu + page. This makes all existing MMU pages obsolete. Obsolete pages can't be + used. Therefore, vCPUs must load a new, valid root before re-entering the + guest. The MMU generation is only ever '0' or '1'. Note, the TDP MMU doesn't + use this field as non-root TDP MMU pages are reachable only from their + owning root. Thus it suffices for TDP MMU to use role.invalid in root pages + to invalidate all MMU pages. gfn: Either the guest page table containing the translations shadowed by this page, or the base page frame for linear translations. See role.direct. @@ -219,21 +231,30 @@ Shadow pages contain the following information: at __pa(sp2->spt). sp2 will point back at sp1 through parent_pte. The spt array forms a DAG structure with the shadow page as a node, and guest pages as leaves. - gfns: - An array of 512 guest frame numbers, one for each present pte. Used to - perform a reverse map from a pte to a gfn. When role.direct is set, any - element of this array can be calculated from the gfn field when used, in - this case, the array of gfns is not allocated. See role.direct and gfn. - root_count: - A counter keeping track of how many hardware registers (guest cr3 or - pdptrs) are now pointing at the page. While this counter is nonzero, the - page cannot be destroyed. See role.invalid. + shadowed_translation: + An array of 512 shadow translation entries, one for each present pte. Used + to perform a reverse map from a pte to a gfn as well as its access + permission. When role.direct is set, the shadow_translation array is not + allocated. This is because the gfn contained in any element of this array + can be calculated from the gfn field when used. In addition, when + role.direct is set, KVM does not track access permission for each of the + gfn. See role.direct and gfn. + root_count / tdp_mmu_root_count: + root_count is a reference counter for root shadow pages in Shadow MMU. + vCPUs elevate the refcount when getting a shadow page that will be used as + a root page, i.e. page that will be loaded into hardware directly (CR3, + PDPTRs, nCR3 EPTP). Root pages cannot be destroyed while their refcount is + non-zero. See role.invalid. tdp_mmu_root_count is similar but exclusively + used in TDP MMU as an atomic refcount. parent_ptes: The reverse mapping for the pte/ptes pointing at this page's spt. If parent_ptes bit 0 is zero, only one spte points at this page and parent_ptes points at this single spte, otherwise, there exists multiple sptes pointing at this page and (parent_ptes & ~0x1) points at a data structure with a list of parent sptes. + ptep: + The kernel virtual address of the SPTE that points at this shadow page. + Used exclusively by the TDP MMU, this field is a union with parent_ptes. unsync: If true, then the translations in this page may not match the guest's translation. This is equivalent to the state of the tlb when a pte is @@ -261,6 +282,10 @@ Shadow pages contain the following information: since the last time the page table was actually used; if emulation is triggered too frequently on this page, KVM will unmap the page to avoid emulation in the future. + tdp_mmu_page: + Is 1 if the shadow page is a TDP MMU page. This variable is used to + bifurcate the control flows for KVM when walking any data structure that + may contain pages from both TDP MMU and shadow MMU. Reverse map =========== |