summaryrefslogtreecommitdiffstats
path: root/Documentation/virt/kvm
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/virt/kvm')
-rw-r--r--Documentation/virt/kvm/api.rst53
-rw-r--r--Documentation/virt/kvm/x86/amd-memory-encryption.rst42
-rw-r--r--Documentation/virt/kvm/x86/msr.rst19
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