Commit 37158943 authored by Suzuki K Poulose's avatar Suzuki K Poulose Committed by Catalin Marinas
Browse files

arm64: rsi: Add support for checking whether an MMIO is protected 



On Arm CCA, with RMM-v1.0, all MMIO regions are shared. However, in
the future, an Arm CCA-v1.0 compliant guest may be run in a lesser
privileged partition in the Realm World (with Arm CCA-v1.1 Planes
feature). In this case, some of the MMIO regions may be emulated
by a higher privileged component in the Realm world, i.e, protected.

Thus the guest must decide today, whether a given MMIO region is shared
vs Protected and create the stage1 mapping accordingly. On Arm CCA, this
detection is based on the "IPA State" (RIPAS == RIPAS_IO). Provide a
helper to run this check on a given range of MMIO.

Also, provide a arm64 helper which may be hooked in by other solutions.

Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Reviewed-by: default avatarGavin Shan <gshan@redhat.com>
Signed-off-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: default avatarSteven Price <steven.price@arm.com>
Link: https://lore.kernel.org/r/20241017131434.40935-5-steven.price@arm.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 39930695

arch/arm64/include/asm/io.h

+8 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <asm/early_ioremap.h>

#include <asm/alternative.h>

#include <asm/cpufeature.h>

#include <asm/rsi.h>



/*

 * Generic IO read/write.  These perform native-endian accesses.
@@ -318,4 +319,11 @@ extern bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size, 
					unsigned long flags);

#define arch_memremap_can_ram_remap arch_memremap_can_ram_remap



static inline bool arm64_is_protected_mmio(phys_addr_t phys_addr, size_t size)

{

	if (unlikely(is_realm_world()))

		return __arm64_is_protected_mmio(phys_addr, size);

	return false;

}



#endif	/* __ASM_IO_H */

arch/arm64/include/asm/rsi.h

+2 −0
Original line number Diff line number Diff line
@@ -14,6 +14,8 @@ DECLARE_STATIC_KEY_FALSE(rsi_present); 


void __init arm64_rsi_init(void);



bool __arm64_is_protected_mmio(phys_addr_t base, size_t size);



static inline bool is_realm_world(void)

{

	return static_branch_unlikely(&rsi_present);

arch/arm64/include/asm/rsi_cmds.h

+21 −0
Original line number Diff line number Diff line
@@ -45,6 +45,27 @@ static inline unsigned long rsi_get_realm_config(struct realm_config *cfg) 
	return res.a0;

}



static inline unsigned long rsi_ipa_state_get(phys_addr_t start,

					      phys_addr_t end,

					      enum ripas *state,

					      phys_addr_t *top)

{

	struct arm_smccc_res res;



	arm_smccc_smc(SMC_RSI_IPA_STATE_GET,

		      start, end, 0, 0, 0, 0, 0,

		      &res);



	if (res.a0 == RSI_SUCCESS) {

		if (top)

			*top = res.a1;

		if (state)

			*state = res.a2;

	}



	return res.a0;

}



static inline long rsi_set_addr_range_state(phys_addr_t start,

					    phys_addr_t end,

					    enum ripas state,

arch/arm64/kernel/rsi.c

+26 −0
Original line number Diff line number Diff line
@@ -67,6 +67,32 @@ static void __init arm64_rsi_setup_memory(void) 
	}

}



bool __arm64_is_protected_mmio(phys_addr_t base, size_t size)

{

	enum ripas ripas;

	phys_addr_t end, top;



	/* Overflow ? */

	if (WARN_ON(base + size <= base))

		return false;



	end = ALIGN(base + size, RSI_GRANULE_SIZE);

	base = ALIGN_DOWN(base, RSI_GRANULE_SIZE);



	while (base < end) {

		if (WARN_ON(rsi_ipa_state_get(base, end, &ripas, &top)))

			break;

		if (WARN_ON(top <= base))

			break;

		if (ripas != RSI_RIPAS_DEV)

			break;

		base = top;

	}



	return base >= end;

}

EXPORT_SYMBOL(__arm64_is_protected_mmio);



void __init arm64_rsi_init(void)

{

	if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_SMC)