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

1 files changed, 16 insertions, 3 deletions

diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
index 006e4cdbeb78..ef3b91797a8b 100644
--- a/include/linux/psp-sev.h
+++ b/include/linux/psp-sev.h
@@ -788,12 +788,25 @@ struct sev_data_snp_shutdown_ex {
 	u32 rsvd1:31;
 } __packed;
 
+/**
+ * struct sev_platform_init_args
+ *
+ * @error: SEV firmware error code
+ * @probe: True if this is being called as part of CCP module probe, which
+ *  will defer SEV_INIT/SEV_INIT_EX firmware initialization until needed
+ *  unless psp_init_on_probe module param is set
+ */
+struct sev_platform_init_args {
+	int error;
+	bool probe;
+};
+
 #ifdef CONFIG_CRYPTO_DEV_SP_PSP
 
 /**
  * sev_platform_init - perform SEV INIT command
  *
- * @error: SEV command return code
+ * @args: struct sev_platform_init_args to pass in arguments
  *
  * Returns:
  * 0 if the SEV successfully processed the command
@@ -802,7 +815,7 @@ struct sev_data_snp_shutdown_ex {
  * -%ETIMEDOUT if the SEV command timed out
  * -%EIO       if the SEV returned a non-zero return code
  */
-int sev_platform_init(int *error);
+int sev_platform_init(struct sev_platform_init_args *args);
 
 /**
  * sev_platform_status - perform SEV PLATFORM_STATUS command
@@ -909,7 +922,7 @@ void *psp_copy_user_blob(u64 uaddr, u32 len);
 static inline int
 sev_platform_status(struct sev_user_data_status *status, int *error) { return -ENODEV; }
 
-static inline int sev_platform_init(int *error) { return -ENODEV; }
+static inline int sev_platform_init(struct sev_platform_init_args *args) { return -ENODEV; }
 
 static inline int
 sev_guest_deactivate(struct sev_data_deactivate *data, int *error) { return -ENODEV; }