crypto: ccp: Handle legacy SEV commands when SNP is enabled

The behavior of legacy SEV commands is altered when the firmware is
initialized for SNP support. In that case, all command buffer memory
that may get written to by legacy SEV commands must be marked as
firmware-owned in the RMP table prior to issuing the command.

Additionally, when a command buffer contains a system physical address
that points to additional buffers that firmware may write to, special
handling is needed depending on whether:

1) the system physical address points to guest memory
2) the system physical address points to host memory

To handle case #1, the pages of these buffers are changed to
firmware-owned in the RMP table before issuing the command, and restored
to hypervisor-owned after the command completes.

For case #2, a bounce buffer is used instead of the original address.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Co-developed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240126041126.1927228-19-michael.roth@amd.com

crypto: ccp: Add support to initialize the AMD-SP for SEV-SNP

Before SNP VMs can be launched, the platform must be appropriately
configured and initialized via the SNP_INIT command.

During the execution of SNP_INIT command, the firmware configures
and enables SNP security policy enforcement in many system components.
Some system components write to regions of memory reserved by early
x86 firmware (e.g. UEFI). Other system components write to regions
provided by the operation system, hypervisor, or x86 firmware.
Such system components can only write to HV-fixed pages or Default
pages. They will error when attempting to write to pages in other page
states after SNP_INIT enables their SNP enforcement.

Starting in SNP firmware v1.52, the SNP_INIT_EX command takes a list of
system physical address ranges to convert into the HV-fixed page states
during the RMP initialization. If INIT_RMP is 1, hypervisors should
provide all system physical address ranges that the hypervisor will
never assign to a guest until the next RMP re-initialization.

For instance, the memory that UEFI reserves should be included in the
range list. This allows system components that occasionally write to
memory (e.g. logging to UEFI reserved regions) to not fail due to
RMP initialization and SNP enablement.

Note that SNP_INIT(_EX) must not be executed while non-SEV guests are
executing, otherwise it is possible that the system could reset or hang.
The psp_init_on_probe module parameter was added for SEV/SEV-ES support
and the init_ex_path module parameter to allow for time for the
necessary file system to be mounted/available.

SNP_INIT(_EX) does not use the file associated with init_ex_path. So, to
avoid running into issues where SNP_INIT(_EX) is called while there are
other running guests, issue it during module probe regardless of the
psp_init_on_probe setting, but maintain the previous deferrable handling
for SEV/SEV-ES initialization.

[ mdr: Squash in psp_init_on_probe changes from Tom, reduce
proliferation of 'probe' function parameter where possible.
bp: Fix 32-bit allmodconfig build. ]

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Co-developed-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Co-developed-by: Jarkko Sakkinen <jarkko@profian.com>
Signed-off-by: Jarkko Sakkinen <jarkko@profian.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240126041126.1927228-14-michael.roth@amd.com

crypto: ccp - Move some PSP mailbox bit definitions into common header

Some of the bits and fields used for mailboxes communicating with the
PSP are common across all mailbox implementations (SEV, TEE, etc).

Move these bits into the common `linux/psp.h` so they don't need to
be re-defined for each implementation.

Acked-by: Rijo Thomas <Rijo-john.Thomas@amd.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: ccp: Use the stack and common buffer for INIT command

Drop the dedicated init_cmd_buf and instead use a local variable. Now
that the low level helper uses an internal buffer for all commands,
using the stack for the upper layers is safe even when running with
CONFIG_VMAP_STACK=y.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210406224952.4177376-8-seanjc@google.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

crypto: ccp: Use the stack and common buffer for status commands

Drop the dedicated status_cmd_buf and instead use a local variable for
PLATFORM_STATUS. Now that the low level helper uses an internal buffer
for all commands, using the stack for the upper layers is safe even when
running with CONFIG_VMAP_STACK=y.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210406224952.4177376-7-seanjc@google.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

crypto: ccp: Play nice with vmalloc'd memory for SEV command structs

Copy the incoming @data comman to an internal buffer so that callers can
put SEV command buffers on the stack without running afoul of
CONFIG_VMAP_STACK=y, i.e. without bombing on vmalloc'd pointers. As of
today, the largest supported command takes a 68 byte buffer, i.e. pretty
much every command can be put on the stack. Because sev_cmd_mutex is
held for the entirety of a transaction, only a single bounce buffer is
required.

Use the internal buffer unconditionally, as the majority of in-kernel
users will soon switch to using the stack. At that point, checking
virt_addr_valid() becomes (negligible) overhead in most cases, and
supporting both paths slightly increases complexity. Since the commands
are all quite small, the cost of the copies is insignificant compared to
the latency of communicating with the PSP.

Allocate a full page for the buffer as opportunistic preparation for
SEV-SNP, which requires the command buffer to be in firmware state for
commands that trigger memory writes from the PSP firmware. Using a full
page now will allow SEV-SNP support to simply transition the page as
needed.

Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210406224952.4177376-5-seanjc@google.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

crypto: ccp - move SEV vdata to a dedicated data structure

PSP can support both SEV and TEE interface. Therefore, move
SEV specific registers to a dedicated data structure.
TEE interface specific registers will be added in a later
patch.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Jens Wiklander <jens.wiklander@linaro.org>
Co-developed-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
Signed-off-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
Signed-off-by: Rijo Thomas <Rijo-john.Thomas@amd.com>
Acked-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: ccp - create a generic psp-dev file

The PSP (Platform Security Processor) provides support for key management
commands in Secure Encrypted Virtualization (SEV) mode, along with
software-based Trusted Execution Environment (TEE) to enable third-party
Trusted Applications.

Therefore, introduce psp-dev.c and psp-dev.h files, which can invoke
SEV (or TEE) initialization based on platform feature support.

TEE interface support will be introduced in a later patch.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Jens Wiklander <jens.wiklander@linaro.org>
Co-developed-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
Signed-off-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
Signed-off-by: Rijo Thomas <Rijo-john.Thomas@amd.com>
Acked-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: ccp - rename psp-dev files to sev-dev

This is a preliminary patch for creating a generic PSP device driver
file, which will have support for both SEV and TEE (Trusted Execution
Environment) interface.

This patch does not introduce any new functionality, but simply renames
psp-dev.c and psp-dev.h files to sev-dev.c and sev-dev.h files
respectively.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Jens Wiklander <jens.wiklander@linaro.org>
Co-developed-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
Signed-off-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
Signed-off-by: Rijo Thomas <Rijo-john.Thomas@amd.com>
Acked-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>