Commit 86edf6bd authored by Shameer Kolothum's avatar Shameer Kolothum Committed by Oliver Upton
Browse files

smccc/kvm_guest: Enable errata based on implementation CPUs 



Retrieve any migration target implementation CPUs using the hypercall
and enable associated errata.

Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
Reviewed-by: default avatarSebastian Ott <sebott@redhat.com>
Signed-off-by: default avatarShameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20250221140229.12588-6-shameerali.kolothum.thodi@huawei.com


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent c8c2647e

arch/arm64/include/asm/cputype.h

+7 −0
Original line number Diff line number Diff line
@@ -276,6 +276,13 @@ static inline bool midr_is_cpu_model_range(u32 midr, u32 model, u32 rv_min, 
	return _model == model && rv >= rv_min && rv <= rv_max;

}



struct target_impl_cpu {

	u64 midr;

	u64 revidr;

	u64 aidr;

};



bool cpu_errata_set_target_impl(u64 num, void *impl_cpus);

bool is_midr_in_range_list(struct midr_range const *ranges);



static inline u64 __attribute_const__ read_cpuid_mpidr(void)

arch/arm64/include/asm/hypervisor.h

+1 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 


void kvm_init_hyp_services(void);

bool kvm_arm_hyp_service_available(u32 func_id);

void kvm_arm_target_impl_cpu_init(void);



#ifdef CONFIG_ARM_PKVM_GUEST

void pkvm_init_hyp_services(void);

arch/arm64/kernel/cpu_errata.c

+40 −5
Original line number Diff line number Diff line
@@ -14,10 +14,34 @@ 
#include <asm/kvm_asm.h>

#include <asm/smp_plat.h>



static u64 target_impl_cpu_num;

static struct target_impl_cpu *target_impl_cpus;



bool cpu_errata_set_target_impl(u64 num, void *impl_cpus)

{

	if (target_impl_cpu_num || !num || !impl_cpus)

		return false;



	target_impl_cpu_num = num;

	target_impl_cpus = impl_cpus;

	return true;

}



static inline bool is_midr_in_range(struct midr_range const *range)

{

	int i;



	if (!target_impl_cpu_num)

		return midr_is_cpu_model_range(read_cpuid_id(), range->model,

					       range->rv_min, range->rv_max);



	for (i = 0; i < target_impl_cpu_num; i++) {

		if (midr_is_cpu_model_range(target_impl_cpus[i].midr,

					    range->model,

					    range->rv_min, range->rv_max))

			return true;

	}

	return false;

}



bool is_midr_in_range_list(struct midr_range const *ranges)
@@ -47,11 +71,22 @@ __is_affected_midr_range(const struct arm64_cpu_capabilities *entry, 
static bool __maybe_unused

is_affected_midr_range(const struct arm64_cpu_capabilities *entry, int scope)

{

	int i;



	if (!target_impl_cpu_num) {

		WARN_ON(scope != SCOPE_LOCAL_CPU || preemptible());

		return __is_affected_midr_range(entry, read_cpuid_id(),

						read_cpuid(REVIDR_EL1));

	}



	for (i = 0; i < target_impl_cpu_num; i++) {

		if (__is_affected_midr_range(entry, target_impl_cpus[i].midr,

					     target_impl_cpus[i].midr))

			return true;

	}

	return false;

}



static bool __maybe_unused

is_affected_midr_range_list(const struct arm64_cpu_capabilities *entry,

			    int scope)

arch/arm64/kernel/cpufeature.c

+2 −0
Original line number Diff line number Diff line
@@ -86,6 +86,7 @@ 
#include <asm/kvm_host.h>

#include <asm/mmu_context.h>

#include <asm/mte.h>

#include <asm/hypervisor.h>

#include <asm/processor.h>

#include <asm/smp.h>

#include <asm/sysreg.h>
@@ -3680,6 +3681,7 @@ unsigned long cpu_get_elf_hwcap3(void) 


static void __init setup_boot_cpu_capabilities(void)

{

	kvm_arm_target_impl_cpu_init();

	/*

	 * The boot CPU's feature register values have been recorded. Detect

	 * boot cpucaps and local cpucaps for the boot CPU, then enable and

drivers/firmware/smccc/kvm_guest.c

+64 −0
Original line number Diff line number Diff line
@@ -6,8 +6,11 @@ 
#include <linux/bitmap.h>

#include <linux/cache.h>

#include <linux/kernel.h>

#include <linux/memblock.h>

#include <linux/string.h>



#include <uapi/linux/psci.h>



#include <asm/hypervisor.h>



static DECLARE_BITMAP(__kvm_arm_hyp_services, ARM_SMCCC_KVM_NUM_FUNCS) __ro_after_init = { };
@@ -51,3 +54,64 @@ bool kvm_arm_hyp_service_available(u32 func_id) 
	return test_bit(func_id, __kvm_arm_hyp_services);

}

EXPORT_SYMBOL_GPL(kvm_arm_hyp_service_available);



void  __init kvm_arm_target_impl_cpu_init(void)

{

	int i;

	u32 ver;

	u64 max_cpus;

	struct arm_smccc_res res;

	struct target_impl_cpu *target;



	if (!kvm_arm_hyp_service_available(ARM_SMCCC_KVM_FUNC_DISCOVER_IMPL_VER) ||

	    !kvm_arm_hyp_service_available(ARM_SMCCC_KVM_FUNC_DISCOVER_IMPL_CPUS))

		return;



	arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_DISCOVER_IMPL_VER_FUNC_ID,

			     0, &res);

	if (res.a0 != SMCCC_RET_SUCCESS)

		return;



	/* Version info is in lower 32 bits and is in SMMCCC_VERSION format */

	ver = lower_32_bits(res.a1);

	if (PSCI_VERSION_MAJOR(ver) != 1) {

		pr_warn("Unsupported target CPU implementation version v%d.%d\n",

			PSCI_VERSION_MAJOR(ver), PSCI_VERSION_MINOR(ver));

		return;

	}



	if (!res.a2) {

		pr_warn("No target implementation CPUs specified\n");

		return;

	}



	max_cpus = res.a2;

	target = memblock_alloc(sizeof(*target) * max_cpus,  __alignof__(*target));

	if (!target) {

		pr_warn("Not enough memory for struct target_impl_cpu\n");

		return;

	}



	for (i = 0; i < max_cpus; i++) {

		arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_DISCOVER_IMPL_CPUS_FUNC_ID,

				     i, &res);

		if (res.a0 != SMCCC_RET_SUCCESS) {

			pr_warn("Discovering target implementation CPUs failed\n");

			goto mem_free;

		}

		target[i].midr = res.a1;

		target[i].revidr = res.a2;

		target[i].aidr = res.a3;

	};



	if (!cpu_errata_set_target_impl(max_cpus, target)) {

		pr_warn("Failed to set target implementation CPUs\n");

		goto mem_free;

	}



	pr_info("Number of target implementation CPUs is %lld\n", max_cpus);

	return;



mem_free:

	memblock_free(target, sizeof(*target) * max_cpus);

}