firmware: arm_rmm: Ensure the RMM has GPT entries for memory

The RMM maintains the state of all the granules in the system to make
sure that the host is abiding by the rules. This state can be maintained
at different granularity, per page (TRACKING_FINE) or per region
(TRACKING_COARSE or TRACKING_INTERMEDIATE). The region size depends on the
underlying "RMI_GRANULE_SIZE". For a "coarse"/"intermediate" region,
all pages in the region must be of the same state, this implies we need to
have "fine" tracking for DRAM, so that we can delegate individual pages.

For now we only support a statically carved out memory for tracking
granules for the "fine" regions. This can be extended in the future to
allow modifying the tracking granularity and remove the need for a
static allocation by the firmware.

Similarly, the firmware may create L0 GPT entries describing the total
address space. But if we change the "PAS" (Physical Address Space) of a
granule, then the firmware may need to create L1 tables to track the PAS
at a finer granularity. Linux therefore checks if the platform firmware
manages the PAR region. i.e., the firmware is in charge of managing the
L1 GPTs (creation and the required memory for the GPT tables - via static
carveouts) without host intervention. Support for dynamic GPT creation by
the host will be added later.

If the firmware requires us to manage the tracking or GPT memory,
deactivate the RMM and reclaim any memory donated at RMM activation.

Apply the same checks when hotplugged memory is brought online.

Reviewed-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Co-developed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/include/linux/arm-rmi-cmds.h b/include/linux/arm-rmi-cmds.h
index dd5380ace4e9..de2da311cc70 100644
--- a/include/linux/arm-rmi-cmds.h
+++ b/include/linux/arm-rmi-cmds.h
@@ -86,4 +86,22 @@ long rmi_sro_execute(struct arm_smccc_1_2_regs *regs);
 	__ret;								\
 })
 
+#ifdef CONFIG_ARM_RMM_RMI
+
+bool is_rmm_active(void);
+bool is_rmi_available(void);
+
+#else
+
+static inline bool is_rmm_active(void)
+{
+	return false;
+}
+
+static inline bool is_rmi_available(void)
+{
+	return false;
+}
+#endif	/* CONFIG_ARM_RMM_RMI */
+
 #endif	/* __LINUX_ARM_RMI_CMDS_H_ */