diff options
Diffstat (limited to 'Documentation/virt/kvm')
| -rw-r--r-- | Documentation/virt/kvm/api.rst | 53 | ||||
| -rw-r--r-- | Documentation/virt/kvm/x86/amd-memory-encryption.rst | 42 | ||||
| -rw-r--r-- | Documentation/virt/kvm/x86/msr.rst | 19 |
3 files changed, 74 insertions, 40 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 09c7e585ff..0b5a33ee71 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -372,7 +372,7 @@ The bits in the dirty bitmap are cleared before the ioctl returns, unless KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is enabled. For more information, see the description of the capability. -Note that the Xen shared info page, if configured, shall always be assumed +Note that the Xen shared_info page, if configured, shall always be assumed to be dirty. KVM will not explicitly mark it such. @@ -5487,8 +5487,9 @@ KVM_PV_ASYNC_CLEANUP_PERFORM __u8 long_mode; __u8 vector; __u8 runstate_update_flag; - struct { + union { __u64 gfn; + __u64 hva; } shared_info; struct { __u32 send_port; @@ -5516,19 +5517,20 @@ type values: KVM_XEN_ATTR_TYPE_LONG_MODE Sets the ABI mode of the VM to 32-bit or 64-bit (long mode). This - determines the layout of the shared info pages exposed to the VM. + determines the layout of the shared_info page exposed to the VM. KVM_XEN_ATTR_TYPE_SHARED_INFO - Sets the guest physical frame number at which the Xen "shared info" + Sets the guest physical frame number at which the Xen shared_info page resides. Note that although Xen places vcpu_info for the first 32 vCPUs in the shared_info page, KVM does not automatically do so - and instead requires that KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO be used - explicitly even when the vcpu_info for a given vCPU resides at the - "default" location in the shared_info page. This is because KVM may - not be aware of the Xen CPU id which is used as the index into the - vcpu_info[] array, so may know the correct default location. - - Note that the shared info page may be constantly written to by KVM; + and instead requires that KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO or + KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO_HVA be used explicitly even when + the vcpu_info for a given vCPU resides at the "default" location + in the shared_info page. This is because KVM may not be aware of + the Xen CPU id which is used as the index into the vcpu_info[] + array, so may know the correct default location. + + Note that the shared_info page may be constantly written to by KVM; it contains the event channel bitmap used to deliver interrupts to a Xen guest, amongst other things. It is exempt from dirty tracking mechanisms — KVM will not explicitly mark the page as dirty each @@ -5537,9 +5539,21 @@ KVM_XEN_ATTR_TYPE_SHARED_INFO any vCPU has been running or any event channel interrupts can be routed to the guest. - Setting the gfn to KVM_XEN_INVALID_GFN will disable the shared info + Setting the gfn to KVM_XEN_INVALID_GFN will disable the shared_info page. +KVM_XEN_ATTR_TYPE_SHARED_INFO_HVA + If the KVM_XEN_HVM_CONFIG_SHARED_INFO_HVA flag is also set in the + Xen capabilities, then this attribute may be used to set the + userspace address at which the shared_info page resides, which + will always be fixed in the VMM regardless of where it is mapped + in guest physical address space. This attribute should be used in + preference to KVM_XEN_ATTR_TYPE_SHARED_INFO as it avoids + unnecessary invalidation of an internal cache when the page is + re-mapped in guest physcial address space. + + Setting the hva to zero will disable the shared_info page. + KVM_XEN_ATTR_TYPE_UPCALL_VECTOR Sets the exception vector used to deliver Xen event channel upcalls. This is the HVM-wide vector injected directly by the hypervisor @@ -5636,6 +5650,21 @@ KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO on dirty logging. Setting the gpa to KVM_XEN_INVALID_GPA will disable the vcpu_info. +KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO_HVA + If the KVM_XEN_HVM_CONFIG_SHARED_INFO_HVA flag is also set in the + Xen capabilities, then this attribute may be used to set the + userspace address of the vcpu_info for a given vCPU. It should + only be used when the vcpu_info resides at the "default" location + in the shared_info page. In this case it is safe to assume the + userspace address will not change, because the shared_info page is + an overlay on guest memory and remains at a fixed host address + regardless of where it is mapped in guest physical address space + and hence unnecessary invalidation of an internal cache may be + avoided if the guest memory layout is modified. + If the vcpu_info does not reside at the "default" location then + it is not guaranteed to remain at the same host address and + hence the aforementioned cache invalidation is required. + KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO Sets the guest physical address of an additional pvclock structure for a given vCPU. This is typically used for guest vsyscall support. diff --git a/Documentation/virt/kvm/x86/amd-memory-encryption.rst b/Documentation/virt/kvm/x86/amd-memory-encryption.rst index 995780088e..84335d119f 100644 --- a/Documentation/virt/kvm/x86/amd-memory-encryption.rst +++ b/Documentation/virt/kvm/x86/amd-memory-encryption.rst @@ -46,21 +46,16 @@ SEV hardware uses ASIDs to associate a memory encryption key with a VM. Hence, the ASID for the SEV-enabled guests must be from 1 to a maximum value defined in the CPUID 0x8000001f[ecx] field. -SEV Key Management -================== +The KVM_MEMORY_ENCRYPT_OP ioctl +=============================== -The SEV guest key management is handled by a separate processor called the AMD -Secure Processor (AMD-SP). Firmware running inside the AMD-SP provides a secure -key management interface to perform common hypervisor activities such as -encrypting bootstrap code, snapshot, migrating and debugging the guest. For more -information, see the SEV Key Management spec [api-spec]_ - -The main ioctl to access SEV is KVM_MEMORY_ENCRYPT_OP. If the argument -to KVM_MEMORY_ENCRYPT_OP is NULL, the ioctl returns 0 if SEV is enabled -and ``ENOTTY`` if it is disabled (on some older versions of Linux, -the ioctl runs normally even with a NULL argument, and therefore will -likely return ``EFAULT``). If non-NULL, the argument to KVM_MEMORY_ENCRYPT_OP -must be a struct kvm_sev_cmd:: +The main ioctl to access SEV is KVM_MEMORY_ENCRYPT_OP, which operates on +the VM file descriptor. If the argument to KVM_MEMORY_ENCRYPT_OP is NULL, +the ioctl returns 0 if SEV is enabled and ``ENOTTY`` if it is disabled +(on some older versions of Linux, the ioctl tries to run normally even +with a NULL argument, and therefore will likely return ``EFAULT`` instead +of zero if SEV is enabled). If non-NULL, the argument to +KVM_MEMORY_ENCRYPT_OP must be a struct kvm_sev_cmd:: struct kvm_sev_cmd { __u32 id; @@ -87,10 +82,6 @@ guests, such as launching, running, snapshotting, migrating and decommissioning. The KVM_SEV_INIT command is used by the hypervisor to initialize the SEV platform context. In a typical workflow, this command should be the first command issued. -The firmware can be initialized either by using its own non-volatile storage or -the OS can manage the NV storage for the firmware using the module parameter -``init_ex_path``. If the file specified by ``init_ex_path`` does not exist or -is invalid, the OS will create or override the file with output from PSP. Returns: 0 on success, -negative on error @@ -434,6 +425,21 @@ issued by the hypervisor to make the guest ready for execution. Returns: 0 on success, -negative on error +Firmware Management +=================== + +The SEV guest key management is handled by a separate processor called the AMD +Secure Processor (AMD-SP). Firmware running inside the AMD-SP provides a secure +key management interface to perform common hypervisor activities such as +encrypting bootstrap code, snapshot, migrating and debugging the guest. For more +information, see the SEV Key Management spec [api-spec]_ + +The AMD-SP firmware can be initialized either by using its own non-volatile +storage or the OS can manage the NV storage for the firmware using +parameter ``init_ex_path`` of the ``ccp`` module. If the file specified +by ``init_ex_path`` does not exist or is invalid, the OS will create or +override the file with PSP non-volatile storage. + References ========== diff --git a/Documentation/virt/kvm/x86/msr.rst b/Documentation/virt/kvm/x86/msr.rst index 9315fc385f..3aecf2a70e 100644 --- a/Documentation/virt/kvm/x86/msr.rst +++ b/Documentation/virt/kvm/x86/msr.rst @@ -193,8 +193,8 @@ data: Asynchronous page fault (APF) control MSR. Bits 63-6 hold 64-byte aligned physical address of a 64 byte memory area - which must be in guest RAM and must be zeroed. This memory is expected - to hold a copy of the following structure:: + which must be in guest RAM. This memory is expected to hold the + following structure:: struct kvm_vcpu_pv_apf_data { /* Used for 'page not present' events delivered via #PF */ @@ -204,7 +204,6 @@ data: __u32 token; __u8 pad[56]; - __u32 enabled; }; Bits 5-4 of the MSR are reserved and should be zero. Bit 0 is set to 1 @@ -232,14 +231,14 @@ data: as regular page fault, guest must reset 'flags' to '0' before it does something that can generate normal page fault. - Bytes 5-7 of 64 byte memory location ('token') will be written to by the + Bytes 4-7 of 64 byte memory location ('token') will be written to by the hypervisor at the time of APF 'page ready' event injection. The content - of these bytes is a token which was previously delivered as 'page not - present' event. The event indicates the page in now available. Guest is - supposed to write '0' to 'token' when it is done handling 'page ready' - event and to write 1' to MSR_KVM_ASYNC_PF_ACK after clearing the location; - writing to the MSR forces KVM to re-scan its queue and deliver the next - pending notification. + of these bytes is a token which was previously delivered in CR2 as + 'page not present' event. The event indicates the page is now available. + Guest is supposed to write '0' to 'token' when it is done handling + 'page ready' event and to write '1' to MSR_KVM_ASYNC_PF_ACK after + clearing the location; writing to the MSR forces KVM to re-scan its + queue and deliver the next pending notification. Note, MSR_KVM_ASYNC_PF_INT MSR specifying the interrupt vector for 'page ready' APF delivery needs to be written to before enabling APF mechanism |