Merge branch 'kvm-arm64/pv-cpuid' into kvmarm/next

* kvm-arm64/pv-cpuid:
  : Paravirtualized implementation ID, courtesy of Shameer Kolothum
  :
  : Big-little has historically been a pain in the ass to virtualize. The
  : implementation ID (MIDR, REVIDR, AIDR) of a vCPU can change at the whim
  : of vCPU scheduling. This can be particularly annoying when the guest
  : needs to know the underlying implementation to mitigate errata.
  :
  : "Hyperscalers" face a similar scheduling problem, where VMs may freely
  : migrate between hosts in a pool of heterogenous hardware. And yes, our
  : server-class friends are equally riddled with errata too.
  :
  : In absence of an architected solution to this wart on the ecosystem,
  : introduce support for paravirtualizing the implementation exposed
  : to a VM, allowing the VMM to describe the pool of implementations that a
  : VM may be exposed to due to scheduling/migration.
  :
  : Userspace is expected to intercept and handle these hypercalls using the
  : SMCCC filter UAPI, should it choose to do so.
  smccc: kvm_guest: Fix kernel builds for 32 bit arm
  KVM: selftests: Add test for KVM_REG_ARM_VENDOR_HYP_BMAP_2
  smccc/kvm_guest: Enable errata based on implementation CPUs
  arm64: Make  _midr_in_range_list() an exported function
  KVM: arm64: Introduce KVM_REG_ARM_VENDOR_HYP_BMAP_2
  KVM: arm64: Specify hypercall ABI for retrieving target implementations
  arm64: Modify _midr_range() functions to read MIDR/REVIDR internally

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

5 files changed, 33 insertions, 26 deletions

diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h
index 6f3f4142e214..cc2d58141be1 100644
--- a/arch/arm64/include/asm/cputype.h
+++ b/arch/arm64/include/asm/cputype.h
@@ -232,6 +232,16 @@
 #define read_cpuid(reg)			read_sysreg_s(SYS_ ## reg)
 
 /*
+ * The CPU ID never changes at run time, so we might as well tell the
+ * compiler that it's constant.  Use this function to read the CPU ID
+ * rather than directly reading processor_id or read_cpuid() directly.
+ */
+static inline u32 __attribute_const__ read_cpuid_id(void)
+{
+	return read_cpuid(MIDR_EL1);
+}
+
+/*
  * Represent a range of MIDR values for a given CPU model and a
  * range of variant/revision values.
  *
@@ -266,30 +276,14 @@ static inline bool midr_is_cpu_model_range(u32 midr, u32 model, u32 rv_min,
 	return _model == model && rv >= rv_min && rv <= rv_max;
 }
 
-static inline bool is_midr_in_range(u32 midr, struct midr_range const *range)
-{
-	return midr_is_cpu_model_range(midr, range->model,
-				       range->rv_min, range->rv_max);
-}
-
-static inline bool
-is_midr_in_range_list(u32 midr, struct midr_range const *ranges)
-{
-	while (ranges->model)
-		if (is_midr_in_range(midr, ranges++))
-			return true;
-	return false;
-}
+struct target_impl_cpu {
+	u64 midr;
+	u64 revidr;
+	u64 aidr;
+};
 
-/*
- * The CPU ID never changes at run time, so we might as well tell the
- * compiler that it's constant.  Use this function to read the CPU ID
- * rather than directly reading processor_id or read_cpuid() directly.
- */
-static inline u32 __attribute_const__ read_cpuid_id(void)
-{
-	return read_cpuid(MIDR_EL1);
-}
+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)
 {
diff --git a/arch/arm64/include/asm/hypervisor.h b/arch/arm64/include/asm/hypervisor.h
index 409e239834d1..a12fd897c877 100644
--- a/arch/arm64/include/asm/hypervisor.h
+++ b/arch/arm64/include/asm/hypervisor.h
@@ -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);
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index a316af8f1e0d..34c43af8b7b7 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -238,7 +238,8 @@ struct kvm_arch_memory_slot {
 struct kvm_smccc_features {
 	unsigned long std_bmap;
 	unsigned long std_hyp_bmap;
-	unsigned long vendor_hyp_bmap;
+	unsigned long vendor_hyp_bmap; /* Function numbers 0-63 */
+	unsigned long vendor_hyp_bmap_2; /* Function numbers 64-127 */
 };
 
 typedef unsigned int pkvm_handle_t;
diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
index 662471cfc536..30a29e88994b 100644
--- a/arch/arm64/include/asm/mmu.h
+++ b/arch/arm64/include/asm/mmu.h
@@ -101,8 +101,7 @@ static inline bool kaslr_requires_kpti(void)
 	if (IS_ENABLED(CONFIG_CAVIUM_ERRATUM_27456)) {
 		extern const struct midr_range cavium_erratum_27456_cpus[];
 
-		if (is_midr_in_range_list(read_cpuid_id(),
-					  cavium_erratum_27456_cpus))
+		if (is_midr_in_range_list(cavium_erratum_27456_cpus))
 			return false;
 	}
 
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index ca6f2ee88060..af9d9acaf997 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -372,6 +372,7 @@ enum {
 #endif
 };
 
+/* Vendor hyper call function numbers 0-63 */
 #define KVM_REG_ARM_VENDOR_HYP_BMAP		KVM_REG_ARM_FW_FEAT_BMAP_REG(2)
 
 enum {
@@ -382,6 +383,17 @@ enum {
 #endif
 };
 
+/* Vendor hyper call function numbers 64-127 */
+#define KVM_REG_ARM_VENDOR_HYP_BMAP_2		KVM_REG_ARM_FW_FEAT_BMAP_REG(3)
+
+enum {
+	KVM_REG_ARM_VENDOR_HYP_BIT_DISCOVER_IMPL_VER	= 0,
+	KVM_REG_ARM_VENDOR_HYP_BIT_DISCOVER_IMPL_CPUS	= 1,
+#ifdef __KERNEL__
+	KVM_REG_ARM_VENDOR_HYP_BMAP_2_BIT_COUNT,
+#endif
+};
+
 /* Device Control API on vm fd */
 #define KVM_ARM_VM_SMCCC_CTRL		0
 #define   KVM_ARM_VM_SMCCC_FILTER	0