On 12/20/21 18:29, Cédric Le Goater wrote:
> On 12/20/21 02:23, Alexey Kardashevskiy wrote:
>> At the moment KVM on PPC creates 4 types of entries under the kvm debugfs:
>> 1) "%pid-%fd" per a KVM instance (for all platforms);
>> 2) "vm%pid" (for PPC Book3s HV KVM);
>> 3) "vm%u_vcpu%u_timing" (for PPC Book3e KVM);
>> 4) "kvm-xive-%p" (for XIVE PPC Book3s KVM, the same for XICS);
>>
>> The problem with this is that multiple VMs per process is not allowed for
>> 2) and 3) which makes it possible for userspace to trigger errors when
>> creating duplicated debugfs entries.
>>
>> This merges all these into 1).
>>
>> This defines kvm_arch_create_kvm_debugfs() similar to
>> kvm_arch_create_vcpu_debugfs().
>>
>> This defines 2 hooks in kvmppc_ops that allow specific KVM implementations
>> add necessary entries, this adds the _e500 suffix to
>> kvmppc_create_vcpu_debugfs_e500() to make it clear what platform it is for.
>>
>> This makes use of already existing kvm_arch_create_vcpu_debugfs() on PPC.
>>
>> This removes no more used debugfs_dir pointers from PPC kvm_arch structs.
>>
>> This stops removing vcpu entries as once created vcpus stay around
>> for the entire life of a VM and removed when the KVM instance is closed,
>> see commit d56f5136b010 ("KVM: let kvm_destroy_vm_debugfs clean up vCPU
>> debugfs directories").
>>
>> Suggested-by: Fabiano Rosas <farosas@xxxxxxxxxxxxx>
>> Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx>
>
> Reviewed-by: Cédric Le Goater <clg@xxxxxxxx>
>
> One comment below.
>
>> ---
>> Changes:
>> v4:
>> * added "kvm-xive-%p"
>>
>> v3:
>> * reworked commit log, especially, the bit about removing vcpus
>>
>> v2:
>> * handled powerpc-booke
>> * s/kvm/vm/ in arch hooks
>> ---
>> arch/powerpc/include/asm/kvm_host.h | 6 ++---
>> arch/powerpc/include/asm/kvm_ppc.h | 2 ++
>> arch/powerpc/kvm/timing.h | 9 ++++----
>> arch/powerpc/kvm/book3s_64_mmu_hv.c | 2 +-
>> arch/powerpc/kvm/book3s_64_mmu_radix.c | 2 +-
>> arch/powerpc/kvm/book3s_hv.c | 31 ++++++++++----------------
>> arch/powerpc/kvm/book3s_xics.c | 13 ++---------
>> arch/powerpc/kvm/book3s_xive.c | 13 ++---------
>> arch/powerpc/kvm/book3s_xive_native.c | 13 ++---------
>> arch/powerpc/kvm/e500.c | 1 +
>> arch/powerpc/kvm/e500mc.c | 1 +
>> arch/powerpc/kvm/powerpc.c | 16 ++++++++++---
>> arch/powerpc/kvm/timing.c | 20 ++++-------------
>> 13 files changed, 47 insertions(+), 82 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
>> index 17263276189e..f5e14fa683f4 100644
>> --- a/arch/powerpc/include/asm/kvm_host.h
>> +++ b/arch/powerpc/include/asm/kvm_host.h
>> @@ -26,6 +26,8 @@
>> #include <asm/hvcall.h>
>> #include <asm/mce.h>
>>
>> +#define __KVM_HAVE_ARCH_VCPU_DEBUGFS
>> +
>> #define KVM_MAX_VCPUS NR_CPUS
>> #define KVM_MAX_VCORES NR_CPUS
>>
>> @@ -295,7 +297,6 @@ struct kvm_arch {
>> bool dawr1_enabled;
>> pgd_t *pgtable;
>> u64 process_table;
>> - struct dentry *debugfs_dir;
>> struct kvm_resize_hpt *resize_hpt; /* protected by kvm->lock */
>> #endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */
>> #ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
>> @@ -673,7 +674,6 @@ struct kvm_vcpu_arch {
>> u64 timing_min_duration[__NUMBER_OF_KVM_EXIT_TYPES];
>> u64 timing_max_duration[__NUMBER_OF_KVM_EXIT_TYPES];
>> u64 timing_last_exit;
>> - struct dentry *debugfs_exit_timing;
>> #endif
>>
>> #ifdef CONFIG_PPC_BOOK3S
>> @@ -829,8 +829,6 @@ struct kvm_vcpu_arch {
>> struct kvmhv_tb_accumulator rm_exit; /* real-mode exit code */
>> struct kvmhv_tb_accumulator guest_time; /* guest execution */
>> struct kvmhv_tb_accumulator cede_time; /* time napping inside guest */
>> -
>> - struct dentry *debugfs_dir;
>> #endif /* CONFIG_KVM_BOOK3S_HV_EXIT_TIMING */
>> };
>>
>> diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
>> index 33db83b82fbd..d2b192dea0d2 100644
>> --- a/arch/powerpc/include/asm/kvm_ppc.h
>> +++ b/arch/powerpc/include/asm/kvm_ppc.h
>> @@ -316,6 +316,8 @@ struct kvmppc_ops {
>> int (*svm_off)(struct kvm *kvm);
>> int (*enable_dawr1)(struct kvm *kvm);
>> bool (*hash_v3_possible)(void);
>> + int (*create_vm_debugfs)(struct kvm *kvm);
>> + int (*create_vcpu_debugfs)(struct kvm_vcpu *vcpu, struct dentry *debugfs_dentry);
>> };
>>
>> extern struct kvmppc_ops *kvmppc_hv_ops;
>> diff --git a/arch/powerpc/kvm/timing.h b/arch/powerpc/kvm/timing.h
>> index feef7885ba82..493a7d510fd5 100644
>> --- a/arch/powerpc/kvm/timing.h
>> +++ b/arch/powerpc/kvm/timing.h
>> @@ -14,8 +14,8 @@
>> #ifdef CONFIG_KVM_EXIT_TIMING
>> void kvmppc_init_timing_stats(struct kvm_vcpu *vcpu);
>> void kvmppc_update_timing_stats(struct kvm_vcpu *vcpu);
>> -void kvmppc_create_vcpu_debugfs(struct kvm_vcpu *vcpu, unsigned int id);
>> -void kvmppc_remove_vcpu_debugfs(struct kvm_vcpu *vcpu);
>> +void kvmppc_create_vcpu_debugfs_e500(struct kvm_vcpu *vcpu,
>> + struct dentry *debugfs_dentry);
>>
>> static inline void kvmppc_set_exit_type(struct kvm_vcpu *vcpu, int type)
>> {
>> @@ -26,9 +26,8 @@ static inline void kvmppc_set_exit_type(struct kvm_vcpu *vcpu, int type)
>> /* if exit timing is not configured there is no need to build the c file */
>> static inline void kvmppc_init_timing_stats(struct kvm_vcpu *vcpu) {}
>> static inline void kvmppc_update_timing_stats(struct kvm_vcpu *vcpu) {}
>> -static inline void kvmppc_create_vcpu_debugfs(struct kvm_vcpu *vcpu,
>> - unsigned int id) {}
>> -static inline void kvmppc_remove_vcpu_debugfs(struct kvm_vcpu *vcpu) {}
>> +static inline void kvmppc_create_vcpu_debugfs_e500(struct kvm_vcpu *vcpu,
>> + struct dentry *debugfs_dentry) {}
>> static inline void kvmppc_set_exit_type(struct kvm_vcpu *vcpu, int type) {}
>> #endif /* CONFIG_KVM_EXIT_TIMING */
>>
>> diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
>> index c63e263312a4..33dae253a0ac 100644
>> --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
>> +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
>> @@ -2112,7 +2112,7 @@ static const struct file_operations debugfs_htab_fops = {
>>
>> void kvmppc_mmu_debugfs_init(struct kvm *kvm)
>> {
>> - debugfs_create_file("htab", 0400, kvm->arch.debugfs_dir, kvm,
>> + debugfs_create_file("htab", 0400, kvm->debugfs_dentry, kvm,
>> &debugfs_htab_fops);
>> }
>>
>> diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
>> index 8cebe5542256..e4ce2a35483f 100644
>> --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
>> +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
>> @@ -1454,7 +1454,7 @@ static const struct file_operations debugfs_radix_fops = {
>>
>> void kvmhv_radix_debugfs_init(struct kvm *kvm)
>> {
>> - debugfs_create_file("radix", 0400, kvm->arch.debugfs_dir, kvm,
>> + debugfs_create_file("radix", 0400, kvm->debugfs_dentry, kvm,
>> &debugfs_radix_fops);
>> }
>>
>> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
>> index bf1eb1160ae2..4c52541b6f37 100644
>> --- a/arch/powerpc/kvm/book3s_hv.c
>> +++ b/arch/powerpc/kvm/book3s_hv.c
>> @@ -2768,20 +2768,17 @@ static const struct file_operations debugfs_timings_ops = {
>> };
>>
>> /* Create a debugfs directory for the vcpu */
>> -static void debugfs_vcpu_init(struct kvm_vcpu *vcpu, unsigned int id)
>> +static int kvmppc_arch_create_vcpu_debugfs_hv(struct kvm_vcpu *vcpu, struct dentry *debugfs_dentry)
>> {
>> - char buf[16];
>> - struct kvm *kvm = vcpu->kvm;
>> -
>> - snprintf(buf, sizeof(buf), "vcpu%u", id);
>> - vcpu->arch.debugfs_dir = debugfs_create_dir(buf, kvm->arch.debugfs_dir);
>> - debugfs_create_file("timings", 0444, vcpu->arch.debugfs_dir, vcpu,
>> + debugfs_create_file("timings", 0444, debugfs_dentry, vcpu,
>> &debugfs_timings_ops);
>> + return 0;
>> }
>>
>> #else /* CONFIG_KVM_BOOK3S_HV_EXIT_TIMING */
>> -static void debugfs_vcpu_init(struct kvm_vcpu *vcpu, unsigned int id)
>> +static int kvmppc_arch_create_vcpu_debugfs_hv(struct kvm_vcpu *vcpu, struct dentry *debugfs_dentry)
>> {
>> + return 0;
>> }
>> #endif /* CONFIG_KVM_BOOK3S_HV_EXIT_TIMING */
>>
>> @@ -2904,8 +2901,6 @@ static int kvmppc_core_vcpu_create_hv(struct kvm_vcpu *vcpu)
>> vcpu->arch.cpu_type = KVM_CPU_3S_64;
>> kvmppc_sanity_check(vcpu);
>>
>> - debugfs_vcpu_init(vcpu, id);
>> -
>> return 0;
>> }
>>
>> @@ -5226,7 +5221,6 @@ void kvmppc_free_host_rm_ops(void)
>> static int kvmppc_core_init_vm_hv(struct kvm *kvm)
>> {
>> unsigned long lpcr, lpid;
>> - char buf[32];
>> int ret;
>>
>> mutex_init(&kvm->arch.uvmem_lock);
>> @@ -5359,15 +5353,14 @@ static int kvmppc_core_init_vm_hv(struct kvm *kvm)
>> kvm->arch.smt_mode = 1;
>> kvm->arch.emul_smt_mode = 1;
>>
>> - /*
>> - * Create a debugfs directory for the VM
>> - */
>> - snprintf(buf, sizeof(buf), "vm%d", current->pid);
>> - kvm->arch.debugfs_dir = debugfs_create_dir(buf, kvm_debugfs_dir);
>> + return 0;
>> +}
>> +
>> +static int kvmppc_arch_create_vm_debugfs_hv(struct kvm *kvm)
>> +{
>> kvmppc_mmu_debugfs_init(kvm);
>> if (radix_enabled())
>> kvmhv_radix_debugfs_init(kvm);
>> -
>> return 0;
>> }
>>
>> @@ -5382,8 +5375,6 @@ static void kvmppc_free_vcores(struct kvm *kvm)
>>
>> static void kvmppc_core_destroy_vm_hv(struct kvm *kvm)
>> {
>> - debugfs_remove_recursive(kvm->arch.debugfs_dir);
>> -
>> if (!cpu_has_feature(CPU_FTR_ARCH_300))
>> kvm_hv_vm_deactivated();
>>
>> @@ -6044,6 +6035,8 @@ static struct kvmppc_ops kvm_ops_hv = {
>> .svm_off = kvmhv_svm_off,
>> .enable_dawr1 = kvmhv_enable_dawr1,
>> .hash_v3_possible = kvmppc_hash_v3_possible,
>> + .create_vcpu_debugfs = kvmppc_arch_create_vcpu_debugfs_hv,
>> + .create_vm_debugfs = kvmppc_arch_create_vm_debugfs_hv,
>> };
>>
>> static int kvm_init_subcore_bitmap(void)
>> diff --git a/arch/powerpc/kvm/book3s_xics.c b/arch/powerpc/kvm/book3s_xics.c
>> index ebd5d920de8c..3dfa9285e4a4 100644
>> --- a/arch/powerpc/kvm/book3s_xics.c
>> +++ b/arch/powerpc/kvm/book3s_xics.c
>> @@ -1016,19 +1016,10 @@ DEFINE_SHOW_ATTRIBUTE(xics_debug);
>>
>> static void xics_debugfs_init(struct kvmppc_xics *xics)
>> {
>> - char *name;
>> -
>> - name = kasprintf(GFP_KERNEL, "kvm-xics-%p", xics);
>> - if (!name) {
>> - pr_err("%s: no memory for name\n", __func__);
>> - return;
>> - }
>> -
>> - xics->dentry = debugfs_create_file(name, 0444, arch_debugfs_dir,
>> + xics->dentry = debugfs_create_file("xics", 0444, xics->kvm->debugfs_dentry,
>> xics, &xics_debug_fops);
>>
>> - pr_debug("%s: created %s\n", __func__, name);
>> - kfree(name);
>> + pr_debug("%s: created\n", __func__);
>> }
>>
>> static struct kvmppc_ics *kvmppc_xics_create_ics(struct kvm *kvm,
>> diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c
>> index 225008882958..bb41afbb68fc 100644
>> --- a/arch/powerpc/kvm/book3s_xive.c
>> +++ b/arch/powerpc/kvm/book3s_xive.c
>> @@ -2351,19 +2351,10 @@ DEFINE_SHOW_ATTRIBUTE(xive_debug);
>>
>> static void xive_debugfs_init(struct kvmppc_xive *xive)
>> {
>> - char *name;
>> -
>> - name = kasprintf(GFP_KERNEL, "kvm-xive-%p", xive);
>> - if (!name) {
>> - pr_err("%s: no memory for name\n", __func__);
>> - return;
>> - }
>> -
>> - xive->dentry = debugfs_create_file(name, S_IRUGO, arch_debugfs_dir,
>> + xive->dentry = debugfs_create_file("xive", S_IRUGO, xive->kvm->debugfs_dentry,
>> xive, &xive_debug_fops);
>
> The KVM XIVE device implements a "xics-on-xive" interface, the XICS hcalls
> on top of the XIVE native PowerNV (OPAL) interface, and ...
>
>> - pr_debug("%s: created %s\n", __func__, name);
>> - kfree(name);
>> + pr_debug("%s: created\n", __func__);
>> }
>>
>> static void kvmppc_xive_init(struct kvm_device *dev)
>> diff --git a/arch/powerpc/kvm/book3s_xive_native.c b/arch/powerpc/kvm/book3s_xive_native.c
>> index 99db9ac49901..e86f5b6c2ae1 100644
>> --- a/arch/powerpc/kvm/book3s_xive_native.c
>> +++ b/arch/powerpc/kvm/book3s_xive_native.c
>> @@ -1259,19 +1259,10 @@ DEFINE_SHOW_ATTRIBUTE(xive_native_debug);
>>
>> static void xive_native_debugfs_init(struct kvmppc_xive *xive)
>> {
>> - char *name;
>> -
>> - name = kasprintf(GFP_KERNEL, "kvm-xive-%p", xive);
>> - if (!name) {
>> - pr_err("%s: no memory for name\n", __func__);
>> - return;
>> - }
>> -
>> - xive->dentry = debugfs_create_file(name, 0444, arch_debugfs_dir,
>> + xive->dentry = debugfs_create_file("xive", 0444, xive->kvm->debugfs_dentry,
>> xive, &xive_native_debug_fops);
>
> ... the KVM XIVE *native* device implements a "xive" interface", the one
> using MMIOs for interrupt management.
>
> May be it's worth making the difference in the user interface ?
The content of these xive files is quite different so I kept the same
name as before, I can change if you think it is worth it, should I? You
are probably the only person who looked at it recently (or ever?) :) Thanks,
>
> Thanks,
>
> C.
>
>>
>> - pr_debug("%s: created %s\n", __func__, name);
>> - kfree(name);
>> + pr_debug("%s: created\n", __func__);
>> }
>>
>> static void kvmppc_xive_native_init(struct kvm_device *dev)
>> diff --git a/arch/powerpc/kvm/e500.c b/arch/powerpc/kvm/e500.c
>> index 7e8b69015d20..c8b2b4478545 100644
>> --- a/arch/powerpc/kvm/e500.c
>> +++ b/arch/powerpc/kvm/e500.c
>> @@ -495,6 +495,7 @@ static struct kvmppc_ops kvm_ops_e500 = {
>> .emulate_op = kvmppc_core_emulate_op_e500,
>> .emulate_mtspr = kvmppc_core_emulate_mtspr_e500,
>> .emulate_mfspr = kvmppc_core_emulate_mfspr_e500,
>> + .create_vcpu_debugfs = kvmppc_create_vcpu_debugfs_e500,
>> };
>>
>> static int __init kvmppc_e500_init(void)
>> diff --git a/arch/powerpc/kvm/e500mc.c b/arch/powerpc/kvm/e500mc.c
>> index 1c189b5aadcc..fa0d8dbbe484 100644
>> --- a/arch/powerpc/kvm/e500mc.c
>> +++ b/arch/powerpc/kvm/e500mc.c
>> @@ -381,6 +381,7 @@ static struct kvmppc_ops kvm_ops_e500mc = {
>> .emulate_op = kvmppc_core_emulate_op_e500,
>> .emulate_mtspr = kvmppc_core_emulate_mtspr_e500,
>> .emulate_mfspr = kvmppc_core_emulate_mfspr_e500,
>> + .create_vcpu_debugfs = kvmppc_create_vcpu_debugfs_e500,
>> };
>>
>> static int __init kvmppc_e500mc_init(void)
>> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
>> index a72920f4f221..2ea73dfcebb2 100644
>> --- a/arch/powerpc/kvm/powerpc.c
>> +++ b/arch/powerpc/kvm/powerpc.c
>> @@ -763,7 +763,6 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
>> goto out_vcpu_uninit;
>>
>> vcpu->arch.waitp = &vcpu->wait;
>> - kvmppc_create_vcpu_debugfs(vcpu, vcpu->vcpu_id);
>> return 0;
>>
>> out_vcpu_uninit:
>> @@ -780,8 +779,6 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
>> /* Make sure we're not using the vcpu anymore */
>> hrtimer_cancel(&vcpu->arch.dec_timer);
>>
>> - kvmppc_remove_vcpu_debugfs(vcpu);
>> -
>> switch (vcpu->arch.irq_type) {
>> case KVMPPC_IRQ_MPIC:
>> kvmppc_mpic_disconnect_vcpu(vcpu->arch.mpic, vcpu);
>> @@ -2505,3 +2502,16 @@ int kvm_arch_init(void *opaque)
>> }
>>
>> EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_ppc_instr);
>> +
>> +void kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu, struct dentry *debugfs_dentry)
>> +{
>> + if (vcpu->kvm->arch.kvm_ops->create_vcpu_debugfs)
>> + vcpu->kvm->arch.kvm_ops->create_vcpu_debugfs(vcpu, debugfs_dentry);
>> +}
>> +
>> +int kvm_arch_create_vm_debugfs(struct kvm *kvm)
>> +{
>> + if (kvm->arch.kvm_ops->create_vm_debugfs)
>> + kvm->arch.kvm_ops->create_vm_debugfs(kvm);
>> + return 0;
>> +}
>> diff --git a/arch/powerpc/kvm/timing.c b/arch/powerpc/kvm/timing.c
>> index ba56a5cbba97..f6d472874c85 100644
>> --- a/arch/powerpc/kvm/timing.c
>> +++ b/arch/powerpc/kvm/timing.c
>> @@ -204,21 +204,9 @@ static const struct file_operations kvmppc_exit_timing_fops = {
>> .release = single_release,
>> };
>>
>> -void kvmppc_create_vcpu_debugfs(struct kvm_vcpu *vcpu, unsigned int id)
>> +void kvmppc_create_vcpu_debugfs_e500(struct kvm_vcpu *vcpu,
>> + struct dentry *debugfs_dentry)
>> {
>> - static char dbg_fname[50];
>> - struct dentry *debugfs_file;
>> -
>> - snprintf(dbg_fname, sizeof(dbg_fname), "vm%u_vcpu%u_timing",
>> - current->pid, id);
>> - debugfs_file = debugfs_create_file(dbg_fname, 0666, kvm_debugfs_dir,
>> - vcpu, &kvmppc_exit_timing_fops);
>> -
>> - vcpu->arch.debugfs_exit_timing = debugfs_file;
>> -}
>> -
>> -void kvmppc_remove_vcpu_debugfs(struct kvm_vcpu *vcpu)
>> -{
>> - debugfs_remove(vcpu->arch.debugfs_exit_timing);
>> - vcpu->arch.debugfs_exit_timing = NULL;
>> + debugfs_create_file("timing", 0666, debugfs_dentry,
>> + vcpu, &kvmppc_exit_timing_fops);
>> }
>>
>
--
Alexey
