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 <[email protected]> Fixes: 32f139551954 ("arm/arm64: KVM: Statically configure the host's view of MPIDR") Signed-off-by: Marc Zyngier <[email protected]> --- 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 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
