KVM: arm64: Create nVHE copy of cpu_logical_map

When KVM starts validating host's PSCI requests, it will need to map
MPIDR back to the CPU ID. To this end, copy cpu_logical_map into nVHE
hyp memory when KVM is initialized.

Only copy the information for CPUs that are online at the point of KVM
initialization so that KVM rejects CPUs whose features were not checked
against the finalized capabilities.

Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-15-dbrazdil@google.com

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index ef519e4826165d9c5588594d8f07a823143222a0..bcd6e5d3c89a6464b555ab5a753a6198a83843f3 100644 (file)
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -64,6 +64,8 @@ static bool vgic_present;
 static DEFINE_PER_CPU(unsigned char, kvm_arm_hardware_enabled);
 DEFINE_STATIC_KEY_FALSE(userspace_irqchip_in_use);
 
+extern u64 kvm_nvhe_sym(__cpu_logical_map)[NR_CPUS];
+
 int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
 {
        return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
@@ -1506,6 +1508,20 @@ static inline void hyp_cpu_pm_exit(void)
 }
 #endif
 
+static void init_cpu_logical_map(void)
+{
+       unsigned int cpu;
+
+       /*
+        * Copy the MPIDR <-> logical CPU ID mapping to hyp.
+        * Only copy the set of online CPUs whose features have been chacked
+        * against the finalized system capabilities. The hypervisor will not
+        * allow any other CPUs from the `possible` set to boot.
+        */
+       for_each_online_cpu(cpu)
+               kvm_nvhe_sym(__cpu_logical_map)[cpu] = cpu_logical_map(cpu);
+}
+
 static int init_common_resources(void)
 {
        return kvm_set_ipa_limit();
@@ -1684,6 +1700,9 @@ static int init_hyp_mode(void)
                }
        }
 
+       if (is_protected_kvm_enabled())
+               init_cpu_logical_map();
+
        return 0;
 
 out_err:

diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-smp.c b/arch/arm64/kvm/hyp/nvhe/hyp-smp.c
index 7b0363b4857f2ec7e0f3e05a5692610c836b2a0e..cbab0c6246e20fdafe100846d7471ab775adda0b 100644 (file)
--- a/arch/arm64/kvm/hyp/nvhe/hyp-smp.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-smp.c
@@ -8,6 +8,22 @@
 #include <asm/kvm_hyp.h>
 #include <asm/kvm_mmu.h>
 
+/*
+ * nVHE copy of data structures tracking available CPU cores.
+ * Only entries for CPUs that were online at KVM init are populated.
+ * Other CPUs should not be allowed to boot because their features were
+ * not checked against the finalized system capabilities.
+ */
+u64 __ro_after_init __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = INVALID_HWID };
+
+u64 cpu_logical_map(unsigned int cpu)
+{
+       if (cpu >= ARRAY_SIZE(__cpu_logical_map))
+               hyp_panic();
+
+       return __cpu_logical_map[cpu];
+}
+
 unsigned long __hyp_per_cpu_offset(unsigned int cpu)
 {
        unsigned long *cpu_base_array;