As part of setting up the host context, we populate its
MPIDR by using cpu_logical_map(). It turns out that contrary
to arm64, cpu_logical_map() on 32bit ARM doesn't return the
*full* MPIDR, but a truncated version.
This leaves the host MPIDR slightly corrupted after the first
run of a VM, since we won't correctly restore the MPIDR on
exit. Oops.
Since we cannot trust cpu_logical_map(), let's adopt a different
strategy. We move the initialization of the host CPU context as
part of the per-CPU initialization (which, in retrospect, makes
a lot of sense), and directly read the MPIDR from the HW. This
is guaranteed to work on both arm and arm64.
Reported-by: Andre Przywara <Andre.Przywara@xxxxxxx>
Fixes: 32f139551954 ("arm/arm64: KVM: Statically configure the host's view of MPIDR")
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
arch/arm/include/asm/kvm_host.h | 5 ++---
arch/arm64/include/asm/kvm_host.h | 5 ++---
virt/kvm/arm/arm.c | 3 ++-
3 files changed, 6 insertions(+), 7 deletions(-)
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index e74e8f408987..df515dff536d 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -147,11 +147,10 @@ struct kvm_host_data {
typedef struct kvm_host_data kvm_host_data_t;
-static inline void kvm_init_host_cpu_context(struct kvm_cpu_context *cpu_ctxt,
- int cpu)
+static inline void kvm_init_host_cpu_context(struct kvm_cpu_context *cpu_ctxt)
{
/* The host's MPIDR is immutable, so let's set it up at boot time */
- cpu_ctxt->cp15[c0_MPIDR] = cpu_logical_map(cpu);
+ cpu_ctxt->cp15[c0_MPIDR] = read_cpuid_mpidr();
}
struct vcpu_reset_state {
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index d9770daf3d7d..d1167fe71f9a 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -484,11 +484,10 @@ struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr);
DECLARE_PER_CPU(kvm_host_data_t, kvm_host_data);
-static inline void kvm_init_host_cpu_context(struct kvm_cpu_context *cpu_ctxt,
- int cpu)
+static inline void kvm_init_host_cpu_context(struct kvm_cpu_context *cpu_ctxt)
{
/* The host's MPIDR is immutable, so let's set it up at boot time */
- cpu_ctxt->sys_regs[MPIDR_EL1] = cpu_logical_map(cpu);
+ cpu_ctxt->sys_regs[MPIDR_EL1] = read_cpuid_mpidr();
}
void __kvm_enable_ssbs(void);
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index bd5c55916d0d..f149c79fd6ef 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -1332,6 +1332,8 @@ static void cpu_hyp_reset(void)
static void cpu_hyp_reinit(void)
{
+ kvm_init_host_cpu_context(&this_cpu_ptr(&kvm_host_data)->host_ctxt);
+
cpu_hyp_reset();
if (is_kernel_in_hyp_mode())
@@ -1569,7 +1571,6 @@ static int init_hyp_mode(void)
kvm_host_data_t *cpu_data;
cpu_data = per_cpu_ptr(&kvm_host_data, cpu);
- kvm_init_host_cpu_context(&cpu_data->host_ctxt, cpu);
err = create_hyp_mappings(cpu_data, cpu_data + 1, PAGE_HYP);
if (err) {
--
2.20.1
