On 2020-11-09 11:32, David Brazdil wrote:
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@xxxxxxxxxx>
---
arch/arm64/kvm/arm.c | 17 +++++++++++++++++
arch/arm64/kvm/hyp/nvhe/percpu.c | 16 ++++++++++++++++
2 files changed, 33 insertions(+)
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 9ba9db2aa7f8..b85b4294b72d 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1481,6 +1481,21 @@ static inline void hyp_cpu_pm_exit(void)
}
#endif
+static void init_cpu_logical_map(void)
+{
+ extern u64 kvm_nvhe_sym(__cpu_logical_map)[NR_CPUS];
+ 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)
+ CHOOSE_NVHE_SYM(__cpu_logical_map)[cpu] = cpu_logical_map(cpu);
+}
+
static int init_common_resources(void)
{
return kvm_set_ipa_limit();
@@ -1659,6 +1674,8 @@ static int init_hyp_mode(void)
}
}
+ init_cpu_logical_map();
+
return 0;
out_err:
diff --git a/arch/arm64/kvm/hyp/nvhe/percpu.c
b/arch/arm64/kvm/hyp/nvhe/percpu.c
index 5fd0c5696907..d0b9dbc2df45 100644
--- a/arch/arm64/kvm/hyp/nvhe/percpu.c
+++ b/arch/arm64/kvm/hyp/nvhe/percpu.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 };
I'm not sure what __ro_after_init means once we get S2 isolation.
+
+u64 cpu_logical_map(int cpu)
nit: is there any reason why "cpu" cannot be unsigned? The thought
of a negative CPU number makes me shiver...
+{
+ if (cpu < 0 || 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;
Overall, this patch would make more sense closer it its use case
(in patch 19). I also don't understand why this lives in percpu.c...
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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