Merge branch 'sev-v9-p2' of https://github.com/codomania/kvm

This part of Secure Encrypted Virtualization (SEV) patch series focuses on KVM
changes required to create and manage SEV guests.

SEV is an extension to the AMD-V architecture which supports running encrypted
virtual machine (VMs) under the control of a hypervisor. Encrypted VMs have their
pages (code and data) secured such that only the guest itself has access to
unencrypted version. Each encrypted VM is associated with a unique encryption key;
if its data is accessed to a different entity using a different key the encrypted
guest's data will be incorrectly decrypted, leading to unintelligible data.
This security model ensures that hypervisor will no longer able to inspect or
alter any guest code or data.

The key management of this feature is handled by a separate processor known as
the AMD Secure Processor (AMD-SP) which is present on AMD SOCs. The SEV Key
Management Specification (see below) provides a set of commands which can be
used by hypervisor to load virtual machine keys through the AMD-SP driver.

The patch series adds a new ioctl in KVM driver (KVM_MEMORY_ENCRYPT_OP). The
ioctl will be used by qemu to issue SEV guest-specific commands defined in Key
Management Specification.

The following links provide additional details:

AMD Memory Encryption white paper:
http://amd-dev.wpengine.netdna-cdn.com/wordpress/media/2013/12/AMD_Memory_Encryption_Whitepaper_v7-Public.pdf

AMD64 Architecture Programmer's Manual:
    http://support.amd.com/TechDocs/24593.pdf
    SME is section 7.10
    SEV is section 15.34

SEV Key Management:
http://support.amd.com/TechDocs/55766_SEV-KM API_Specification.pdf

KVM Forum Presentation:
http://www.linux-kvm.org/images/7/74/02x08A-Thomas_Lendacky-AMDs_Virtualizatoin_Memory_Encryption_Technology.pdf

SEV Guest BIOS support:
  SEV support has been add to EDKII/OVMF BIOS
  https://github.com/tianocore/edk2

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 300 insertions, 0 deletions

diff --git a/Documentation/virtual/kvm/00-INDEX b/Documentation/virtual/kvm/00-INDEX
index 69fe1a8b7ad1..3da73aabff5a 100644
--- a/Documentation/virtual/kvm/00-INDEX
+++ b/Documentation/virtual/kvm/00-INDEX
@@ -26,3 +26,6 @@ s390-diag.txt
 	- Diagnose hypercall description (for IBM S/390)
 timekeeping.txt
 	- timekeeping virtualization for x86-based architectures.
+amd-memory-encryption.txt
+	- notes on AMD Secure Encrypted Virtualization feature and SEV firmware
+	  command description
diff --git a/Documentation/virtual/kvm/amd-memory-encryption.rst b/Documentation/virtual/kvm/amd-memory-encryption.rst
new file mode 100644
index 000000000000..71d6d257074f
--- /dev/null
+++ b/Documentation/virtual/kvm/amd-memory-encryption.rst
@@ -0,0 +1,247 @@
+======================================
+Secure Encrypted Virtualization (SEV)
+======================================
+
+Overview
+========
+
+Secure Encrypted Virtualization (SEV) is a feature found on AMD processors.
+
+SEV is an extension to the AMD-V architecture which supports running
+virtual machines (VMs) under the control of a hypervisor. When enabled,
+the memory contents of a VM will be transparently encrypted with a key
+unique to that VM.
+
+The hypervisor can determine the SEV support through the CPUID
+instruction. The CPUID function 0x8000001f reports information related
+to SEV::
+
+	0x8000001f[eax]:
+			Bit[1] 	indicates support for SEV
+	    ...
+		  [ecx]:
+			Bits[31:0]  Number of encrypted guests supported simultaneously
+
+If support for SEV is present, MSR 0xc001_0010 (MSR_K8_SYSCFG) and MSR 0xc001_0015
+(MSR_K7_HWCR) can be used to determine if it can be enabled::
+
+	0xc001_0010:
+		Bit[23]	   1 = memory encryption can be enabled
+			   0 = memory encryption can not be enabled
+
+	0xc001_0015:
+		Bit[0]	   1 = memory encryption can be enabled
+			   0 = memory encryption can not be enabled
+
+When SEV support is available, it can be enabled in a specific VM by
+setting the SEV bit before executing VMRUN.::
+
+	VMCB[0x90]:
+		Bit[1]	    1 = SEV is enabled
+			    0 = SEV is disabled
+
+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 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]_
+
+KVM implements the following commands to support common lifecycle events of SEV
+guests, such as launching, running, snapshotting, migrating and decommissioning.
+
+1. KVM_SEV_INIT
+---------------
+
+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.
+
+Returns: 0 on success, -negative on error
+
+2. KVM_SEV_LAUNCH_START
+-----------------------
+
+The KVM_SEV_LAUNCH_START command is used for creating the memory encryption
+context. To create the encryption context, user must provide a guest policy,
+the owner's public Diffie-Hellman (PDH) key and session information.
+
+Parameters: struct  kvm_sev_launch_start (in/out)
+
+Returns: 0 on success, -negative on error
+
+::
+
+        struct kvm_sev_launch_start {
+                __u32 handle;           /* if zero then firmware creates a new handle */
+                __u32 policy;           /* guest's policy */
+
+                __u64 dh_uaddr;         /* userspace address pointing to the guest owner's PDH key */
+                __u32 dh_len;
+
+                __u64 session_addr;     /* userspace address which points to the guest session information */
+                __u32 session_len;
+        };
+
+On success, the 'handle' field contains a new handle and on error, a negative value.
+
+For more details, see SEV spec Section 6.2.
+
+3. KVM_SEV_LAUNCH_UPDATE_DATA
+-----------------------------
+
+The KVM_SEV_LAUNCH_UPDATE_DATA is used for encrypting a memory region. It also
+calculates a measurement of the memory contents. The measurement is a signature
+of the memory contents that can be sent to the guest owner as an attestation
+that the memory was encrypted correctly by the firmware.
+
+Parameters (in): struct  kvm_sev_launch_update_data
+
+Returns: 0 on success, -negative on error
+
+::
+
+        struct kvm_sev_launch_update {
+                __u64 uaddr;    /* userspace address to be encrypted (must be 16-byte aligned) */
+                __u32 len;      /* length of the data to be encrypted (must be 16-byte aligned) */
+        };
+
+For more details, see SEV spec Section 6.3.
+
+4. KVM_SEV_LAUNCH_MEASURE
+-------------------------
+
+The KVM_SEV_LAUNCH_MEASURE command is used to retrieve the measurement of the
+data encrypted by the KVM_SEV_LAUNCH_UPDATE_DATA command. The guest owner may
+wait to provide the guest with confidential information until it can verify the
+measurement. Since the guest owner knows the initial contents of the guest at
+boot, the measurement can be verified by comparing it to what the guest owner
+expects.
+
+Parameters (in): struct  kvm_sev_launch_measure
+
+Returns: 0 on success, -negative on error
+
+::
+
+        struct kvm_sev_launch_measure {
+                __u64 uaddr;    /* where to copy the measurement */
+                __u32 len;      /* length of measurement blob */
+        };
+
+For more details on the measurement verification flow, see SEV spec Section 6.4.
+
+5. KVM_SEV_LAUNCH_FINISH
+------------------------
+
+After completion of the launch flow, the KVM_SEV_LAUNCH_FINISH command can be
+issued to make the guest ready for the execution.
+
+Returns: 0 on success, -negative on error
+
+6. KVM_SEV_GUEST_STATUS
+-----------------------
+
+The KVM_SEV_GUEST_STATUS command is used to retrieve status information about a
+SEV-enabled guest.
+
+Parameters (out): struct kvm_sev_guest_status
+
+Returns: 0 on success, -negative on error
+
+::
+
+        struct kvm_sev_guest_status {
+                __u32 handle;   /* guest handle */
+                __u32 policy;   /* guest policy */
+                __u8 state;     /* guest state (see enum below) */
+        };
+
+SEV guest state:
+
+::
+
+        enum {
+        SEV_STATE_INVALID = 0;
+        SEV_STATE_LAUNCHING,    /* guest is currently being launched */
+        SEV_STATE_SECRET,       /* guest is being launched and ready to accept the ciphertext data */
+        SEV_STATE_RUNNING,      /* guest is fully launched and running */
+        SEV_STATE_RECEIVING,    /* guest is being migrated in from another SEV machine */
+        SEV_STATE_SENDING       /* guest is getting migrated out to another SEV machine */
+        };
+
+7. KVM_SEV_DBG_DECRYPT
+----------------------
+
+The KVM_SEV_DEBUG_DECRYPT command can be used by the hypervisor to request the
+firmware to decrypt the data at the given memory region.
+
+Parameters (in): struct kvm_sev_dbg
+
+Returns: 0 on success, -negative on error
+
+::
+
+        struct kvm_sev_dbg {
+                __u64 src_uaddr;        /* userspace address of data to decrypt */
+                __u64 dst_uaddr;        /* userspace address of destination */
+                __u32 len;              /* length of memory region to decrypt */
+        };
+
+The command returns an error if the guest policy does not allow debugging.
+
+8. KVM_SEV_DBG_ENCRYPT
+----------------------
+
+The KVM_SEV_DEBUG_ENCRYPT command can be used by the hypervisor to request the
+firmware to encrypt the data at the given memory region.
+
+Parameters (in): struct kvm_sev_dbg
+
+Returns: 0 on success, -negative on error
+
+::
+
+        struct kvm_sev_dbg {
+                __u64 src_uaddr;        /* userspace address of data to encrypt */
+                __u64 dst_uaddr;        /* userspace address of destination */
+                __u32 len;              /* length of memory region to encrypt */
+        };
+
+The command returns an error if the guest policy does not allow debugging.
+
+9. KVM_SEV_LAUNCH_SECRET
+------------------------
+
+The KVM_SEV_LAUNCH_SECRET command can be used by the hypervisor to inject secret
+data after the measurement has been validated by the guest owner.
+
+Parameters (in): struct kvm_sev_launch_secret
+
+Returns: 0 on success, -negative on error
+
+::
+
+        struct kvm_sev_launch_secret {
+                __u64 hdr_uaddr;        /* userspace address containing the packet header */
+                __u32 hdr_len;
+
+                __u64 guest_uaddr;      /* the guest memory region where the secret should be injected */
+                __u32 guest_len;
+
+                __u64 trans_uaddr;      /* the hypervisor memory region which contains the secret */
+                __u32 trans_len;
+        };
+
+References
+==========
+
+.. [white-paper] http://amd-dev.wpengine.netdna-cdn.com/wordpress/media/2013/12/AMD_Memory_Encryption_Whitepaper_v7-Public.pdf
+.. [api-spec] http://support.amd.com/TechDocs/55766_SEV-KM%20API_Specification.pdf
+.. [amd-apm] http://support.amd.com/TechDocs/24593.pdf (section 15.34)
+.. [kvm-forum]  http://www.linux-kvm.org/images/7/74/02x08A-Thomas_Lendacky-AMDs_Virtualizatoin_Memory_Encryption_Technology.pdf
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 57d3ee9e4bde..e5f1743e0b3e 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3403,6 +3403,56 @@ invalid, if invalid pages are written to (e.g. after the end of memory)
 or if no page table is present for the addresses (e.g. when using
 hugepages).
 
+4.109 KVM_MEMORY_ENCRYPT_OP
+
+Capability: basic
+Architectures: x86
+Type: system
+Parameters: an opaque platform specific structure (in/out)
+Returns: 0 on success; -1 on error
+
+If the platform supports creating encrypted VMs then this ioctl can be used
+for issuing platform-specific memory encryption commands to manage those
+encrypted VMs.
+
+Currently, this ioctl is used for issuing Secure Encrypted Virtualization
+(SEV) commands on AMD Processors. The SEV commands are defined in
+Documentation/virtual/kvm/amd-memory-encryption.txt.
+
+4.110 KVM_MEMORY_ENCRYPT_REG_REGION
+
+Capability: basic
+Architectures: x86
+Type: system
+Parameters: struct kvm_enc_region (in)
+Returns: 0 on success; -1 on error
+
+This ioctl can be used to register a guest memory region which may
+contain encrypted data (e.g. guest RAM, SMRAM etc).
+
+It is used in the SEV-enabled guest. When encryption is enabled, a guest
+memory region may contain encrypted data. The SEV memory encryption
+engine uses a tweak such that two identical plaintext pages, each at
+different locations will have differing ciphertexts. So swapping or
+moving ciphertext of those pages will not result in plaintext being
+swapped. So relocating (or migrating) physical backing pages for the SEV
+guest will require some additional steps.
+
+Note: The current SEV key management spec does not provide commands to
+swap or migrate (move) ciphertext pages. Hence, for now we pin the guest
+memory region registered with the ioctl.
+
+4.111 KVM_MEMORY_ENCRYPT_UNREG_REGION
+
+Capability: basic
+Architectures: x86
+Type: system
+Parameters: struct kvm_enc_region (in)
+Returns: 0 on success; -1 on error
+
+This ioctl can be used to unregister the guest memory region registered
+with KVM_MEMORY_ENCRYPT_REG_REGION ioctl above.
+
 5. The kvm_run structure
 ------------------------