Re: [PATCH RFC v3 8/9] KVM: implement kvm_for_each_vcpu with a list

From: Christoffer Dall
Date: Tue Aug 29 2017 - 05:59:14 EST

On Mon, Aug 21, 2017 at 10:35:29PM +0200, Radim KrÄmÃÅ wrote:
> Going through all VCPUs is more natural with a list and the RCU list can
> work as lockless with our constraints.
>
> This makes kvm->vcpus lose most users, so it will be easier to make
> something out of it.
>
> A nice side-effect is that the first argument to the macro is gone.
> ARM code was changed a bit to cope with the loss when working with a
> range 0-n and most other places switched to vcpu->vcpus_idx.
>
> Signed-off-by: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
> ---
> arch/mips/kvm/mips.c | 4 +---
> arch/powerpc/kvm/book3s_32_mmu.c | 3 +--
> arch/powerpc/kvm/book3s_64_mmu.c | 3 +--
> arch/powerpc/kvm/book3s_hv.c | 7 +++----
> arch/powerpc/kvm/book3s_pr.c | 5 ++---
> arch/powerpc/kvm/book3s_xics.c | 2 +-
> arch/powerpc/kvm/book3s_xics.h | 3 +--
> arch/powerpc/kvm/book3s_xive.c | 18 ++++++++----------
> arch/powerpc/kvm/book3s_xive.h | 3 +--
> arch/powerpc/kvm/e500_emulate.c | 3 +--
> arch/powerpc/kvm/powerpc.c | 3 +--
> arch/s390/kvm/interrupt.c | 3 +--
> arch/s390/kvm/kvm-s390.c | 31 ++++++++++---------------------
> arch/s390/kvm/kvm-s390.h | 6 ++----
> arch/s390/kvm/sigp.c | 3 +--
> arch/x86/kvm/hyperv.c | 3 +--
> arch/x86/kvm/i8254.c | 3 +--
> arch/x86/kvm/i8259.c | 7 +++----
> arch/x86/kvm/ioapic.c | 3 +--
> arch/x86/kvm/irq_comm.c | 10 +++++-----
> arch/x86/kvm/lapic.c | 5 ++---
> arch/x86/kvm/svm.c | 3 +--
> arch/x86/kvm/vmx.c | 3 +--
> arch/x86/kvm/x86.c | 25 ++++++++++---------------
> include/linux/kvm_host.h | 30 +++++++++++++-----------------
> virt/kvm/arm/arch_timer.c | 10 ++++------
> virt/kvm/arm/arm.c | 12 ++++--------
> virt/kvm/arm/pmu.c | 3 +--
> virt/kvm/arm/psci.c | 7 +++----
> virt/kvm/arm/vgic/vgic-init.c | 11 +++++------
> virt/kvm/arm/vgic/vgic-kvm-device.c | 28 ++++++++++++++++------------
> virt/kvm/arm/vgic/vgic-mmio-v2.c | 5 ++---
> virt/kvm/arm/vgic/vgic-mmio-v3.c | 19 +++++++++++--------
> virt/kvm/arm/vgic/vgic.c | 3 +--
> virt/kvm/kvm_main.c | 22 +++++++++++-----------
> 35 files changed, 131 insertions(+), 178 deletions(-)
>
> diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
> index 770c40b9df37..c841cb434486 100644
> --- a/arch/mips/kvm/mips.c
> +++ b/arch/mips/kvm/mips.c
> @@ -162,12 +162,10 @@ int kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu)
>
> void kvm_arch_free_vcpus(struct kvm *kvm)
> {
> - unsigned int i;
> struct kvm_vcpu *vcpu;
>
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm)
> kvm_arch_vcpu_free(vcpu);
> - }
> }
>
> static void kvm_mips_free_gpa_pt(struct kvm *kvm)
> diff --git a/arch/powerpc/kvm/book3s_32_mmu.c b/arch/powerpc/kvm/book3s_32_mmu.c
> index 1992676c7a94..1ac7cace49fc 100644
> --- a/arch/powerpc/kvm/book3s_32_mmu.c
> +++ b/arch/powerpc/kvm/book3s_32_mmu.c
> @@ -353,11 +353,10 @@ static void kvmppc_mmu_book3s_32_mtsrin(struct kvm_vcpu *vcpu, u32 srnum,
>
> static void kvmppc_mmu_book3s_32_tlbie(struct kvm_vcpu *vcpu, ulong ea, bool large)
> {
> - int i;
> struct kvm_vcpu *v;
>
> /* flush this VA on all cpus */
> - kvm_for_each_vcpu(i, v, vcpu->kvm)
> + kvm_for_each_vcpu(v, vcpu->kvm)
> kvmppc_mmu_pte_flush(v, ea, 0x0FFFF000);
> }
>
> diff --git a/arch/powerpc/kvm/book3s_64_mmu.c b/arch/powerpc/kvm/book3s_64_mmu.c
> index 29ebe2fd5867..7b043fcc8c88 100644
> --- a/arch/powerpc/kvm/book3s_64_mmu.c
> +++ b/arch/powerpc/kvm/book3s_64_mmu.c
> @@ -534,7 +534,6 @@ static void kvmppc_mmu_book3s_64_tlbie(struct kvm_vcpu *vcpu, ulong va,
> bool large)
> {
> u64 mask = 0xFFFFFFFFFULL;
> - long i;
> struct kvm_vcpu *v;
>
> dprintk("KVM MMU: tlbie(0x%lx)\n", va);
> @@ -559,7 +558,7 @@ static void kvmppc_mmu_book3s_64_tlbie(struct kvm_vcpu *vcpu, ulong va,
> mask = 0xFFFFFF000ULL;
> }
> /* flush this VA on all vcpus */
> - kvm_for_each_vcpu(i, v, vcpu->kvm)
> + kvm_for_each_vcpu(v, vcpu->kvm)
> kvmppc_mmu_pte_vflush(v, va >> 12, mask);
> }
>
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 359c79cdf0cc..4d40537fad20 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -1253,9 +1253,8 @@ static void kvmppc_set_lpcr(struct kvm_vcpu *vcpu, u64 new_lpcr,
> */
> if ((new_lpcr & LPCR_ILE) != (vc->lpcr & LPCR_ILE)) {
> struct kvm_vcpu *vcpu;
> - int i;
>
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> if (vcpu->arch.vcore != vc)
> continue;
> if (new_lpcr & LPCR_ILE)
> @@ -3347,7 +3346,7 @@ static int kvm_vm_ioctl_get_dirty_log_hv(struct kvm *kvm,
> {
> struct kvm_memslots *slots;
> struct kvm_memory_slot *memslot;
> - int i, r;
> + int r;
> unsigned long n;
> unsigned long *buf;
> struct kvm_vcpu *vcpu;
> @@ -3381,7 +3380,7 @@ static int kvm_vm_ioctl_get_dirty_log_hv(struct kvm *kvm,
>
> /* Harvest dirty bits from VPA and DTL updates */
> /* Note: we never modify the SLB shadow buffer areas */
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> spin_lock(&vcpu->arch.vpa_update_lock);
> kvmppc_harvest_vpa_dirty(&vcpu->arch.vpa, memslot, buf);
> kvmppc_harvest_vpa_dirty(&vcpu->arch.dtl, memslot, buf);
> diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
> index 69a09444d46e..9ef1b9b7e48a 100644
> --- a/arch/powerpc/kvm/book3s_pr.c
> +++ b/arch/powerpc/kvm/book3s_pr.c
> @@ -251,7 +251,6 @@ static int kvmppc_core_check_requests_pr(struct kvm_vcpu *vcpu)
> static void do_kvm_unmap_hva(struct kvm *kvm, unsigned long start,
> unsigned long end)
> {
> - long i;
> struct kvm_vcpu *vcpu;
> struct kvm_memslots *slots;
> struct kvm_memory_slot *memslot;
> @@ -272,7 +271,7 @@ static void do_kvm_unmap_hva(struct kvm *kvm, unsigned long start,
> */
> gfn = hva_to_gfn_memslot(hva_start, memslot);
> gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot);
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> kvmppc_mmu_pte_pflush(vcpu, gfn << PAGE_SHIFT,
> gfn_end << PAGE_SHIFT);
> }
> @@ -1593,7 +1592,7 @@ static int kvm_vm_ioctl_get_dirty_log_pr(struct kvm *kvm,
> ga = memslot->base_gfn << PAGE_SHIFT;
> ga_end = ga + (memslot->npages << PAGE_SHIFT);
>
> - kvm_for_each_vcpu(n, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> kvmppc_mmu_pte_pflush(vcpu, ga, ga_end);
>
> n = kvm_dirty_bitmap_bytes(memslot);
> diff --git a/arch/powerpc/kvm/book3s_xics.c b/arch/powerpc/kvm/book3s_xics.c
> index d329b2add7e2..9871b76368bd 100644
> --- a/arch/powerpc/kvm/book3s_xics.c
> +++ b/arch/powerpc/kvm/book3s_xics.c
> @@ -966,7 +966,7 @@ static int xics_debug_show(struct seq_file *m, void *private)
>
> seq_printf(m, "=========\nICP state\n=========\n");
>
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> struct kvmppc_icp *icp = vcpu->arch.icp;
> union kvmppc_icp_state state;
>
> diff --git a/arch/powerpc/kvm/book3s_xics.h b/arch/powerpc/kvm/book3s_xics.h
> index 453c9e518c19..71e33af1e119 100644
> --- a/arch/powerpc/kvm/book3s_xics.h
> +++ b/arch/powerpc/kvm/book3s_xics.h
> @@ -119,9 +119,8 @@ static inline struct kvmppc_icp *kvmppc_xics_find_server(struct kvm *kvm,
> u32 nr)
> {
> struct kvm_vcpu *vcpu = NULL;
> - int i;
>
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> if (vcpu->arch.icp && nr == vcpu->arch.icp->server_num)
> return vcpu->arch.icp;
> }
> diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c
> index 08b200a0bbce..22222a540439 100644
> --- a/arch/powerpc/kvm/book3s_xive.c
> +++ b/arch/powerpc/kvm/book3s_xive.c
> @@ -182,7 +182,7 @@ static int xive_check_provisioning(struct kvm *kvm, u8 prio)
> {
> struct kvmppc_xive *xive = kvm->arch.xive;
> struct kvm_vcpu *vcpu;
> - int i, rc;
> + int rc;
>
> lockdep_assert_held(&kvm->lock);
>
> @@ -193,7 +193,7 @@ static int xive_check_provisioning(struct kvm *kvm, u8 prio)
> pr_devel("Provisioning prio... %d\n", prio);
>
> /* Provision each VCPU and enable escalations */
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> if (!vcpu->arch.xive_vcpu)
> continue;
> rc = xive_provision_queue(vcpu, prio);
> @@ -252,7 +252,7 @@ static int xive_try_pick_queue(struct kvm_vcpu *vcpu, u8 prio)
> static int xive_select_target(struct kvm *kvm, u32 *server, u8 prio)
> {
> struct kvm_vcpu *vcpu;
> - int i, rc;
> + int rc;
>
> /* Locate target server */
> vcpu = kvmppc_xive_find_server(kvm, *server);
> @@ -271,7 +271,7 @@ static int xive_select_target(struct kvm *kvm, u32 *server, u8 prio)
> pr_devel(" .. failed, looking up candidate...\n");
>
> /* Failed, pick another VCPU */
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> if (!vcpu->arch.xive_vcpu)
> continue;
> rc = xive_try_pick_queue(vcpu, prio);
> @@ -1237,7 +1237,7 @@ static void xive_pre_save_queue(struct kvmppc_xive *xive, struct xive_q *q)
> static void xive_pre_save_scan(struct kvmppc_xive *xive)
> {
> struct kvm_vcpu *vcpu = NULL;
> - int i, j;
> + int j;
>
> /*
> * See comment in xive_get_source() about how this
> @@ -1252,7 +1252,7 @@ static void xive_pre_save_scan(struct kvmppc_xive *xive)
> }
>
> /* Then scan the queues and update the "in_queue" flag */
> - kvm_for_each_vcpu(i, vcpu, xive->kvm) {
> + kvm_for_each_vcpu(vcpu, xive->kvm) {
> struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
> if (!xc)
> continue;
> @@ -1418,9 +1418,8 @@ static bool xive_check_delayed_irq(struct kvmppc_xive *xive, u32 irq)
> {
> struct kvm *kvm = xive->kvm;
> struct kvm_vcpu *vcpu = NULL;
> - int i;
>
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
>
> if (!xc)
> @@ -1787,14 +1786,13 @@ static int xive_debug_show(struct seq_file *m, void *private)
> u64 t_vm_h_cppr = 0;
> u64 t_vm_h_eoi = 0;
> u64 t_vm_h_ipi = 0;
> - unsigned int i;
>
> if (!kvm)
> return 0;
>
> seq_printf(m, "=========\nVCPU state\n=========\n");
>
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
>
> if (!xc)
> diff --git a/arch/powerpc/kvm/book3s_xive.h b/arch/powerpc/kvm/book3s_xive.h
> index 5938f7644dc1..5bc33db0924c 100644
> --- a/arch/powerpc/kvm/book3s_xive.h
> +++ b/arch/powerpc/kvm/book3s_xive.h
> @@ -175,9 +175,8 @@ struct kvmppc_xive_vcpu {
> static inline struct kvm_vcpu *kvmppc_xive_find_server(struct kvm *kvm, u32 nr)
> {
> struct kvm_vcpu *vcpu = NULL;
> - int i;
>
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> if (vcpu->arch.xive_vcpu && nr == vcpu->arch.xive_vcpu->server_num)
> return vcpu;
> }
> diff --git a/arch/powerpc/kvm/e500_emulate.c b/arch/powerpc/kvm/e500_emulate.c
> index 990db69a1d0b..56151681afcc 100644
> --- a/arch/powerpc/kvm/e500_emulate.c
> +++ b/arch/powerpc/kvm/e500_emulate.c
> @@ -68,13 +68,12 @@ static int kvmppc_e500_emul_msgsnd(struct kvm_vcpu *vcpu, int rb)
> ulong param = vcpu->arch.gpr[rb];
> int prio = dbell2prio(rb);
> int pir = param & PPC_DBELL_PIR_MASK;
> - int i;
> struct kvm_vcpu *cvcpu;
>
> if (prio < 0)
> return EMULATE_FAIL;
>
> - kvm_for_each_vcpu(i, cvcpu, vcpu->kvm) {
> + kvm_for_each_vcpu(cvcpu, vcpu->kvm) {
> int cpir = cvcpu->arch.shared->pir;
> if ((param & PPC_DBELL_MSG_BRDCAST) || (cpir == pir)) {
> set_bit(prio, &cvcpu->arch.pending_exceptions);
> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> index 1c563545473c..633d3bb501c1 100644
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -458,10 +458,9 @@ int kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu)
>
> void kvm_arch_free_vcpus(struct kvm *kvm)
> {
> - int i;
> struct kvm_vcpu *vcpu;
>
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> kvm_arch_vcpu_free(vcpu);
> }
>
> diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
> index a619ddae610d..d503b25638af 100644
> --- a/arch/s390/kvm/interrupt.c
> +++ b/arch/s390/kvm/interrupt.c
> @@ -2287,7 +2287,6 @@ static int flic_ais_mode_set_all(struct kvm *kvm, struct kvm_device_attr *attr)
> static int flic_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
> {
> int r = 0;
> - unsigned int i;
> struct kvm_vcpu *vcpu;
>
> switch (attr->group) {
> @@ -2308,7 +2307,7 @@ static int flic_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
> * about late coming workers.
> */
> synchronize_srcu(&dev->kvm->srcu);
> - kvm_for_each_vcpu(i, vcpu, dev->kvm)
> + kvm_for_each_vcpu(vcpu, dev->kvm)
> kvm_clear_async_pf_completion_queue(vcpu);
> break;
> case KVM_DEV_FLIC_ADAPTER_REGISTER:
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index bb6278d45a25..3e64e3eb2a63 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -174,12 +174,11 @@ static int kvm_clock_sync(struct notifier_block *notifier, unsigned long val,
> {
> struct kvm *kvm;
> struct kvm_vcpu *vcpu;
> - int i;
> unsigned long long *delta = v;
>
> list_for_each_entry(kvm, &vm_list, vm_list) {
> kvm->arch.epoch -= *delta;
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> vcpu->arch.sie_block->epoch -= *delta;
> if (vcpu->arch.cputm_enabled)
> vcpu->arch.cputm_start += *delta;
> @@ -491,12 +490,10 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
>
> static void icpt_operexc_on_all_vcpus(struct kvm *kvm)
> {
> - unsigned int i;
> struct kvm_vcpu *vcpu;
>
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm)
> kvm_s390_sync_request(KVM_REQ_ICPT_OPEREXC, vcpu);
> - }
> }
>
> static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
> @@ -705,7 +702,6 @@ static void kvm_s390_vcpu_crypto_setup(struct kvm_vcpu *vcpu);
> static int kvm_s390_vm_set_crypto(struct kvm *kvm, struct kvm_device_attr *attr)
> {
> struct kvm_vcpu *vcpu;
> - int i;
>
> if (!test_kvm_facility(kvm, 76))
> return -EINVAL;
> @@ -743,7 +739,7 @@ static int kvm_s390_vm_set_crypto(struct kvm *kvm, struct kvm_device_attr *attr)
> return -ENXIO;
> }
>
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> kvm_s390_vcpu_crypto_setup(vcpu);
> exit_sie(vcpu);
> }
> @@ -753,10 +749,9 @@ static int kvm_s390_vm_set_crypto(struct kvm *kvm, struct kvm_device_attr *attr)
>
> static void kvm_s390_sync_request_broadcast(struct kvm *kvm, int req)
> {
> - int cx;
> struct kvm_vcpu *vcpu;
>
> - kvm_for_each_vcpu(cx, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> kvm_s390_sync_request(req, vcpu);
> }
>
> @@ -1943,10 +1938,9 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
>
> void kvm_arch_free_vcpus(struct kvm *kvm)
> {
> - unsigned int i;
> struct kvm_vcpu *vcpu;
>
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> kvm_arch_vcpu_destroy(vcpu);
> }
>
> @@ -2050,7 +2044,6 @@ static int sca_switch_to_extended(struct kvm *kvm)
> struct bsca_block *old_sca = kvm->arch.sca;
> struct esca_block *new_sca;
> struct kvm_vcpu *vcpu;
> - unsigned int vcpu_idx;
> u32 scaol, scaoh;
>
> new_sca = alloc_pages_exact(sizeof(*new_sca), GFP_KERNEL|__GFP_ZERO);
> @@ -2065,7 +2058,7 @@ static int sca_switch_to_extended(struct kvm *kvm)
>
> sca_copy_b_to_e(new_sca, old_sca);
>
> - kvm_for_each_vcpu(vcpu_idx, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> vcpu->arch.sie_block->scaoh = scaoh;
> vcpu->arch.sie_block->scaol = scaol;
> vcpu->arch.sie_block->ecb2 |= ECB2_ESCA;
> @@ -2491,14 +2484,13 @@ static void kvm_gmap_notifier(struct gmap *gmap, unsigned long start,
> struct kvm *kvm = gmap->private;
> struct kvm_vcpu *vcpu;
> unsigned long prefix;
> - int i;
>
> if (gmap_is_shadow(gmap))
> return;
> if (start >= 1UL << 31)
> /* We are only interested in prefix pages */
> return;
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> /* match against both prefix pages */
> prefix = kvm_s390_get_prefix(vcpu);
> if (prefix <= end && start <= prefix + 2*PAGE_SIZE - 1) {
> @@ -2856,13 +2848,12 @@ static int kvm_s390_handle_requests(struct kvm_vcpu *vcpu)
> void kvm_s390_set_tod_clock(struct kvm *kvm, u64 tod)
> {
> struct kvm_vcpu *vcpu;
> - int i;
>
> mutex_lock(&kvm->lock);
> preempt_disable();
> kvm->arch.epoch = tod - get_tod_clock();
> kvm_s390_vcpu_block_all(kvm);
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> vcpu->arch.sie_block->epoch = kvm->arch.epoch;
> kvm_s390_vcpu_unblock_all(kvm);
> preempt_enable();
> @@ -3389,12 +3380,10 @@ static void __disable_ibs_on_vcpu(struct kvm_vcpu *vcpu)
>
> static void __disable_ibs_on_all_vcpus(struct kvm *kvm)
> {
> - unsigned int i;
> struct kvm_vcpu *vcpu;
>
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm)
> __disable_ibs_on_vcpu(vcpu);
> - }
> }
>
> static void __enable_ibs_on_vcpu(struct kvm_vcpu *vcpu)
> @@ -3462,7 +3451,7 @@ void kvm_s390_vcpu_stop(struct kvm_vcpu *vcpu)
> * As we only have one VCPU left, we want to enable the IBS
> * facility for that VCPU to speed it up.
> */
> - kvm_for_each_vcpu(i, started_vcpu, vcpu->kvm)
> + kvm_for_each_vcpu(started_vcpu, vcpu->kvm)
> if (!is_vcpu_stopped(started_vcpu)) {
> __enable_ibs_on_vcpu(started_vcpu);
> break;
> diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
> index 6fedc8bc7a37..6077a724630c 100644
> --- a/arch/s390/kvm/kvm-s390.h
> +++ b/arch/s390/kvm/kvm-s390.h
> @@ -294,20 +294,18 @@ int kvm_s390_handle_diag(struct kvm_vcpu *vcpu);
>
> static inline void kvm_s390_vcpu_block_all(struct kvm *kvm)
> {
> - int i;
> struct kvm_vcpu *vcpu;
>
> WARN_ON(!mutex_is_locked(&kvm->lock));
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> kvm_s390_vcpu_block(vcpu);
> }
>
> static inline void kvm_s390_vcpu_unblock_all(struct kvm *kvm)
> {
> - int i;
> struct kvm_vcpu *vcpu;
>
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> kvm_s390_vcpu_unblock(vcpu);
> }
>
> diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c
> index 1a252f537081..a31e1c2a994d 100644
> --- a/arch/s390/kvm/sigp.c
> +++ b/arch/s390/kvm/sigp.c
> @@ -158,7 +158,6 @@ static int __sigp_stop_and_store_status(struct kvm_vcpu *vcpu,
> static int __sigp_set_arch(struct kvm_vcpu *vcpu, u32 parameter)
> {
> int rc;
> - unsigned int i;
> struct kvm_vcpu *v;
>
> switch (parameter & 0xff) {
> @@ -167,7 +166,7 @@ static int __sigp_set_arch(struct kvm_vcpu *vcpu, u32 parameter)
> break;
> case 1:
> case 2:
> - kvm_for_each_vcpu(i, v, vcpu->kvm) {
> + kvm_for_each_vcpu(v, vcpu->kvm) {
> v->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;
> kvm_clear_async_pf_completion_queue(v);
> }
> diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
> index dc97f2544b6f..b43cb27bf783 100644
> --- a/arch/x86/kvm/hyperv.c
> +++ b/arch/x86/kvm/hyperv.c
> @@ -109,13 +109,12 @@ static int synic_set_sint(struct kvm_vcpu_hv_synic *synic, int sint,
> static struct kvm_vcpu *get_vcpu_by_vpidx(struct kvm *kvm, u32 vpidx)
> {
> struct kvm_vcpu *vcpu = NULL;
> - int i;
>
> if (vpidx < KVM_MAX_VCPUS)
> vcpu = kvm_get_vcpu(kvm, vpidx);
> if (vcpu && vcpu_to_hv_vcpu(vcpu)->vp_index == vpidx)
> return vcpu;
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> if (vcpu_to_hv_vcpu(vcpu)->vp_index == vpidx)
> return vcpu;
> return NULL;
> diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
> index af192895b1fc..fdd3bff598f3 100644
> --- a/arch/x86/kvm/i8254.c
> +++ b/arch/x86/kvm/i8254.c
> @@ -241,7 +241,6 @@ static void pit_do_work(struct kthread_work *work)
> struct kvm_pit *pit = container_of(work, struct kvm_pit, expired);
> struct kvm *kvm = pit->kvm;
> struct kvm_vcpu *vcpu;
> - int i;
> struct kvm_kpit_state *ps = &pit->pit_state;
>
> if (atomic_read(&ps->reinject) && !atomic_xchg(&ps->irq_ack, 0))
> @@ -260,7 +259,7 @@ static void pit_do_work(struct kthread_work *work)
> * also be simultaneously delivered through PIC and IOAPIC.
> */
> if (atomic_read(&kvm->arch.vapics_in_nmi_mode) > 0)
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> kvm_apic_nmi_wd_deliver(vcpu);
> }
>
> diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
> index bdcd4139eca9..c4f57fbd7316 100644
> --- a/arch/x86/kvm/i8259.c
> +++ b/arch/x86/kvm/i8259.c
> @@ -50,14 +50,13 @@ static void pic_unlock(struct kvm_pic *s)
> {
> bool wakeup = s->wakeup_needed;
> struct kvm_vcpu *vcpu;
> - int i;
>
> s->wakeup_needed = false;
>
> spin_unlock(&s->lock);
>
> if (wakeup) {
> - kvm_for_each_vcpu(i, vcpu, s->kvm) {
> + kvm_for_each_vcpu(vcpu, s->kvm) {
> if (kvm_apic_accept_pic_intr(vcpu)) {
> kvm_make_request(KVM_REQ_EVENT, vcpu);
> kvm_vcpu_kick(vcpu);
> @@ -270,7 +269,7 @@ int kvm_pic_read_irq(struct kvm *kvm)
>
> static void kvm_pic_reset(struct kvm_kpic_state *s)
> {
> - int irq, i;
> + int irq;
> struct kvm_vcpu *vcpu;
> u8 edge_irr = s->irr & ~s->elcr;
> bool found = false;
> @@ -287,7 +286,7 @@ static void kvm_pic_reset(struct kvm_kpic_state *s)
> }
> s->init_state = 1;
>
> - kvm_for_each_vcpu(i, vcpu, s->pics_state->kvm)
> + kvm_for_each_vcpu(vcpu, s->pics_state->kvm)
> if (kvm_apic_accept_pic_intr(vcpu)) {
> found = true;
> break;
> diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c
> index 1a29da6c0558..2216e6d34fb7 100644
> --- a/arch/x86/kvm/ioapic.c
> +++ b/arch/x86/kvm/ioapic.c
> @@ -146,13 +146,12 @@ void kvm_rtc_eoi_tracking_restore_one(struct kvm_vcpu *vcpu)
> static void kvm_rtc_eoi_tracking_restore_all(struct kvm_ioapic *ioapic)
> {
> struct kvm_vcpu *vcpu;
> - int i;
>
> if (RTC_GSI >= IOAPIC_NUM_PINS)
> return;
>
> rtc_irq_eoi_tracking_reset(ioapic);
> - kvm_for_each_vcpu(i, vcpu, ioapic->kvm)
> + kvm_for_each_vcpu(vcpu, ioapic->kvm)
> __rtc_irq_eoi_tracking_restore_one(vcpu);
> }
>
> diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
> index 3cc3b2d130a0..a8f777f2b0e6 100644
> --- a/arch/x86/kvm/irq_comm.c
> +++ b/arch/x86/kvm/irq_comm.c
> @@ -58,7 +58,7 @@ static int kvm_set_ioapic_irq(struct kvm_kernel_irq_routing_entry *e,
> int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
> struct kvm_lapic_irq *irq, struct dest_map *dest_map)
> {
> - int i, r = -1;
> + int r = -1;
> struct kvm_vcpu *vcpu, *lowest = NULL;
> unsigned long dest_vcpu_bitmap[BITS_TO_LONGS(KVM_MAX_VCPUS)];
> unsigned int dest_vcpus = 0;
> @@ -74,7 +74,7 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
>
> memset(dest_vcpu_bitmap, 0, sizeof(dest_vcpu_bitmap));
>
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> if (!kvm_apic_present(vcpu))
> continue;
>
> @@ -93,7 +93,7 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
> else if (kvm_apic_compare_prio(vcpu, lowest) < 0)
> lowest = vcpu;
> } else {
> - __set_bit(i, dest_vcpu_bitmap);
> + __set_bit(vcpu->vcpus_idx, dest_vcpu_bitmap);
> dest_vcpus++;
> }
> }
> @@ -335,13 +335,13 @@ int kvm_set_routing_entry(struct kvm *kvm,
> bool kvm_intr_is_single_vcpu(struct kvm *kvm, struct kvm_lapic_irq *irq,
> struct kvm_vcpu **dest_vcpu)
> {
> - int i, r = 0;
> + int r = 0;
> struct kvm_vcpu *vcpu;
>
> if (kvm_intr_is_single_vcpu_fast(kvm, irq, dest_vcpu))
> return true;
>
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> if (!kvm_apic_present(vcpu))
> continue;
>
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index 4f38818db929..a7cdd6baa38b 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -166,12 +166,11 @@ static void recalculate_apic_map(struct kvm *kvm)
> {
> struct kvm_apic_map *new, *old = NULL;
> struct kvm_vcpu *vcpu;
> - int i;
> u32 max_id = 255; /* enough space for any xAPIC ID */
>
> mutex_lock(&kvm->arch.apic_map_lock);
>
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> if (kvm_apic_present(vcpu))
> max_id = max(max_id, kvm_x2apic_id(vcpu->arch.apic));
>
> @@ -183,7 +182,7 @@ static void recalculate_apic_map(struct kvm *kvm)
>
> new->max_apic_id = max_id;
>
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> struct kvm_lapic *apic = vcpu->arch.apic;
> struct kvm_lapic **cluster;
> u16 mask;
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 1fa9ee5660f4..605c18003f55 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -3807,7 +3807,6 @@ static int avic_incomplete_ipi_interception(struct vcpu_svm *svm)
> kvm_lapic_reg_write(apic, APIC_ICR, icrl);
> break;
> case AVIC_IPI_FAILURE_TARGET_NOT_RUNNING: {
> - int i;
> struct kvm_vcpu *vcpu;
> struct kvm *kvm = svm->vcpu.kvm;
> struct kvm_lapic *apic = svm->vcpu.arch.apic;
> @@ -3817,7 +3816,7 @@ static int avic_incomplete_ipi_interception(struct vcpu_svm *svm)
> * set the appropriate IRR bits on the valid target
> * vcpus. So, we just need to kick the appropriate vcpu.
> */
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> bool m = kvm_apic_match_dest(vcpu, apic,
> icrl & KVM_APIC_SHORT_MASK,
> GET_APIC_DEST_FIELD(icrh),
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index df8d2f127508..ae0f04e26fec 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -8472,7 +8472,6 @@ static void vmx_flush_pml_buffer(struct kvm_vcpu *vcpu)
> */
> static void kvm_flush_pml_buffers(struct kvm *kvm)
> {
> - int i;
> struct kvm_vcpu *vcpu;
> /*
> * We only need to kick vcpu out of guest mode here, as PML buffer
> @@ -8480,7 +8479,7 @@ static void kvm_flush_pml_buffers(struct kvm *kvm)
> * vcpus running in guest are possible to have unflushed GPAs in PML
> * buffer.
> */
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> kvm_vcpu_kick(vcpu);
> }
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index d021746f1fdf..caea24d3ddb0 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -1734,7 +1734,6 @@ void kvm_make_mclock_inprogress_request(struct kvm *kvm)
> static void kvm_gen_update_masterclock(struct kvm *kvm)
> {
> #ifdef CONFIG_X86_64
> - int i;
> struct kvm_vcpu *vcpu;
> struct kvm_arch *ka = &kvm->arch;
>
> @@ -1743,11 +1742,11 @@ static void kvm_gen_update_masterclock(struct kvm *kvm)
> /* no guest entries from this point */
> pvclock_update_vm_gtod_copy(kvm);
>
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
>
> /* guest entries allowed */
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> kvm_clear_request(KVM_REQ_MCLOCK_INPROGRESS, vcpu);
>
> spin_unlock(&ka->pvclock_gtod_sync_lock);
> @@ -1945,14 +1944,13 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
>
> static void kvmclock_update_fn(struct work_struct *work)
> {
> - int i;
> struct delayed_work *dwork = to_delayed_work(work);
> struct kvm_arch *ka = container_of(dwork, struct kvm_arch,
> kvmclock_update_work);
> struct kvm *kvm = container_of(ka, struct kvm, arch);
> struct kvm_vcpu *vcpu;
>
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
> kvm_vcpu_kick(vcpu);
> }
> @@ -5844,7 +5842,7 @@ static int kvmclock_cpufreq_notifier(struct notifier_block *nb, unsigned long va
> struct cpufreq_freqs *freq = data;
> struct kvm *kvm;
> struct kvm_vcpu *vcpu;
> - int i, send_ipi = 0;
> + int send_ipi = 0;
>
> /*
> * We allow guests to temporarily run on slowing clocks,
> @@ -5894,7 +5892,7 @@ static int kvmclock_cpufreq_notifier(struct notifier_block *nb, unsigned long va
>
> spin_lock(&kvm_lock);
> list_for_each_entry(kvm, &vm_list, vm_list) {
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> if (vcpu->cpu != freq->cpu)
> continue;
> kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
> @@ -6035,11 +6033,10 @@ static void pvclock_gtod_update_fn(struct work_struct *work)
> struct kvm *kvm;
>
> struct kvm_vcpu *vcpu;
> - int i;
>
> spin_lock(&kvm_lock);
> list_for_each_entry(kvm, &vm_list, vm_list)
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu);
> atomic_set(&kvm_guest_has_master_clock, 0);
> spin_unlock(&kvm_lock);
> @@ -7783,7 +7780,6 @@ int kvm_arch_hardware_enable(void)
> {
> struct kvm *kvm;
> struct kvm_vcpu *vcpu;
> - int i;
> int ret;
> u64 local_tsc;
> u64 max_tsc = 0;
> @@ -7797,7 +7793,7 @@ int kvm_arch_hardware_enable(void)
> local_tsc = rdtsc();
> stable = !check_tsc_unstable();
> list_for_each_entry(kvm, &vm_list, vm_list) {
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> if (!stable && vcpu->cpu == smp_processor_id())
> kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
> if (stable && vcpu->arch.last_host_tsc > local_tsc) {
> @@ -7850,7 +7846,7 @@ int kvm_arch_hardware_enable(void)
> u64 delta_cyc = max_tsc - local_tsc;
> list_for_each_entry(kvm, &vm_list, vm_list) {
> kvm->arch.backwards_tsc_observed = true;
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> vcpu->arch.tsc_offset_adjustment += delta_cyc;
> vcpu->arch.last_host_tsc = local_tsc;
> kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu);
> @@ -8079,17 +8075,16 @@ static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu)
>
> void kvm_arch_free_vcpus(struct kvm *kvm)
> {
> - unsigned int i;
> struct kvm_vcpu *vcpu;
>
> /*
> * Unpin any mmu pages first.
> */
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> kvm_clear_async_pf_completion_queue(vcpu);
> kvm_unload_vcpu_mmu(vcpu);
> }
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> kvm_arch_vcpu_free(vcpu);
> }
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index a8b9aa563834..5417dac55272 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -216,6 +216,7 @@ struct kvm_mmio_fragment {
>
> struct kvm_vcpu {
> struct kvm *kvm;
> + struct list_head vcpu_list;
> #ifdef CONFIG_PREEMPT_NOTIFIERS
> struct preempt_notifier preempt_notifier;
> #endif
> @@ -393,6 +394,7 @@ struct kvm {
> struct mm_struct *mm; /* userspace tied to this vm */
> struct kvm_memslots __rcu *memslots[KVM_ADDRESS_SPACE_NUM];
> struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
> + struct list_head vcpu_list;
>
> /*
> * created_vcpus is protected by kvm->lock, and is incremented
> @@ -402,7 +404,7 @@ struct kvm {
> */
> atomic_t online_vcpus;
> int created_vcpus;
> - int last_boosted_vcpu;
> + struct kvm_vcpu *last_boosted_vcpu;
> struct list_head vm_list;
> struct mutex lock;
> struct kvm_io_bus __rcu *buses[KVM_NR_BUSES];
> @@ -492,29 +494,23 @@ static inline struct kvm_vcpu *kvm_get_vcpu(struct kvm *kvm, int i)
> return kvm->vcpus[i];
> }
>
> -#define kvm_for_each_vcpu(idx, vcpup, kvm) \
> - for (idx = 0; \
> - idx < atomic_read(&kvm->online_vcpus) && \
> - (vcpup = kvm_get_vcpu(kvm, idx)) != NULL; \
> - idx++)
> +#define kvm_for_each_vcpu(vcpup, kvm) \
> + list_for_each_entry_rcu(vcpup, &kvm->vcpu_list, vcpu_list)
>
> -#define kvm_for_each_vcpu_from(idx, vcpup, from, kvm) \
> - for (idx = from, vcpup = kvm_get_vcpu(kvm, idx); \
> +#define kvm_for_each_vcpu_from(vcpup, from, kvm) \
> + for (vcpup = from; \
> vcpup; \
> ({ \
> - idx++; \
> - if (idx >= atomic_read(&kvm->online_vcpus)) \
> - idx = 0; \
> - if (idx == from) \
> + vcpup = list_entry_rcu(vcpup->vcpu_list.next, typeof(*vcpup), vcpu_list); \
> + if (&vcpup->vcpu_list == &kvm->vcpu_list) \
> + vcpup = list_entry_rcu(kvm->vcpu_list.next, typeof(*vcpup), vcpu_list); \
> + if (vcpup == from) \
> vcpup = NULL; \
> - else \
> - vcpup = kvm_get_vcpu(kvm, idx); \
> - }))
> + }))
>
> static inline struct kvm_vcpu *kvm_get_vcpu_by_id(struct kvm *kvm, int id)
> {
> struct kvm_vcpu *vcpu = NULL;
> - int i;
>
> if (id < 0)
> return NULL;
> @@ -522,7 +518,7 @@ static inline struct kvm_vcpu *kvm_get_vcpu_by_id(struct kvm *kvm, int id)
> vcpu = kvm_get_vcpu(kvm, id);
> if (vcpu && vcpu->vcpu_id == id)
> return vcpu;
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> if (vcpu->vcpu_id == id)
> return vcpu;
> return NULL;
> diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
> index 8e89d63005c7..3e311fa5c7a1 100644
> --- a/virt/kvm/arm/arch_timer.c
> +++ b/virt/kvm/arm/arch_timer.c
> @@ -478,12 +478,11 @@ int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu)
> /* Make the updates of cntvoff for all vtimer contexts atomic */
> static void update_vtimer_cntvoff(struct kvm_vcpu *vcpu, u64 cntvoff)
> {
> - int i;
> struct kvm *kvm = vcpu->kvm;
> struct kvm_vcpu *tmp;
>
> mutex_lock(&kvm->lock);
> - kvm_for_each_vcpu(i, tmp, kvm)
> + kvm_for_each_vcpu(tmp, kvm)
> vcpu_vtimer(tmp)->cntvoff = cntvoff;
>
> /*
> @@ -622,7 +621,7 @@ void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu)
> static bool timer_irqs_are_valid(struct kvm_vcpu *vcpu)
> {
> int vtimer_irq, ptimer_irq;
> - int i, ret;
> + int ret;
>
> vtimer_irq = vcpu_vtimer(vcpu)->irq.irq;
> ret = kvm_vgic_set_owner(vcpu, vtimer_irq, vcpu_vtimer(vcpu));
> @@ -634,7 +633,7 @@ static bool timer_irqs_are_valid(struct kvm_vcpu *vcpu)
> if (ret)
> return false;
>
> - kvm_for_each_vcpu(i, vcpu, vcpu->kvm) {
> + kvm_for_each_vcpu(vcpu, vcpu->kvm) {
> if (vcpu_vtimer(vcpu)->irq.irq != vtimer_irq ||
> vcpu_ptimer(vcpu)->irq.irq != ptimer_irq)
> return false;
> @@ -720,9 +719,8 @@ void kvm_timer_init_vhe(void)
> static void set_timer_irqs(struct kvm *kvm, int vtimer_irq, int ptimer_irq)
> {
> struct kvm_vcpu *vcpu;
> - int i;
>
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> vcpu_vtimer(vcpu)->irq.irq = vtimer_irq;
> vcpu_ptimer(vcpu)->irq.irq = ptimer_irq;
> }
> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> index d63aa1107fdb..e105f6b307cc 100644
> --- a/virt/kvm/arm/arm.c
> +++ b/virt/kvm/arm/arm.c
> @@ -168,10 +168,9 @@ int kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
>
> void kvm_arch_free_vcpus(struct kvm *kvm)
> {
> - int i;
> struct kvm_vcpu *vcpu;
>
> - for_each_online_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> kvm_arch_vcpu_free(vcpu);
> }
>
> @@ -548,20 +547,18 @@ bool kvm_arch_intc_initialized(struct kvm *kvm)
>
> void kvm_arm_halt_guest(struct kvm *kvm)
> {
> - int i;
> struct kvm_vcpu *vcpu;
>
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> vcpu->arch.pause = true;
> kvm_make_all_cpus_request(kvm, KVM_REQ_SLEEP);
> }
>
> void kvm_arm_resume_guest(struct kvm *kvm)
> {
> - int i;
> struct kvm_vcpu *vcpu;
>
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> vcpu->arch.pause = false;
> swake_up(kvm_arch_vcpu_wq(vcpu));
> }
> @@ -1440,10 +1437,9 @@ static void check_kvm_target_cpu(void *ret)
> struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr)
> {
> struct kvm_vcpu *vcpu;
> - int i;
>
> mpidr &= MPIDR_HWID_BITMASK;
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> if (mpidr == kvm_vcpu_get_mpidr_aff(vcpu))
> return vcpu;
> }
> diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
> index 8a9c42366db7..84f526cfdb35 100644
> --- a/virt/kvm/arm/pmu.c
> +++ b/virt/kvm/arm/pmu.c
> @@ -512,10 +512,9 @@ static int kvm_arm_pmu_v3_init(struct kvm_vcpu *vcpu)
> */
> static bool pmu_irq_is_valid(struct kvm *kvm, int irq)
> {
> - int i;
> struct kvm_vcpu *vcpu;
>
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> + kvm_for_each_vcpu(vcpu, kvm) {
> if (!kvm_arm_pmu_irq_initialized(vcpu))
> continue;
>
> diff --git a/virt/kvm/arm/psci.c b/virt/kvm/arm/psci.c
> index f1e363bab5e8..876c965e0886 100644
> --- a/virt/kvm/arm/psci.c
> +++ b/virt/kvm/arm/psci.c
> @@ -129,7 +129,7 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
>
> static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
> {
> - int i, matching_cpus = 0;
> + int matching_cpus = 0;
> unsigned long mpidr;
> unsigned long target_affinity;
> unsigned long target_affinity_mask;
> @@ -152,7 +152,7 @@ static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
> * If one or more VCPU matching target affinity are running
> * then ON else OFF
> */
> - kvm_for_each_vcpu(i, tmp, kvm) {
> + kvm_for_each_vcpu(tmp, kvm) {
> mpidr = kvm_vcpu_get_mpidr_aff(tmp);
> if ((mpidr & target_affinity_mask) == target_affinity) {
> matching_cpus++;
> @@ -169,7 +169,6 @@ static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
>
> static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
> {
> - int i;
> struct kvm_vcpu *tmp;
>
> /*
> @@ -181,7 +180,7 @@ static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
> * after this call is handled and before the VCPUs have been
> * re-initialized.
> */
> - kvm_for_each_vcpu(i, tmp, vcpu->kvm)
> + kvm_for_each_vcpu(tmp, vcpu->kvm)
> tmp->arch.power_off = true;
> kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
>
> diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
> index feb766f74c34..c926d7b30149 100644
> --- a/virt/kvm/arm/vgic/vgic-init.c
> +++ b/virt/kvm/arm/vgic/vgic-init.c
> @@ -119,7 +119,7 @@ void kvm_vgic_vcpu_early_init(struct kvm_vcpu *vcpu)
> */
> int kvm_vgic_create(struct kvm *kvm, u32 type)
> {
> - int i, ret;
> + int ret;
> struct kvm_vcpu *vcpu;
>
> if (irqchip_in_kernel(kvm))
> @@ -143,7 +143,7 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
> if (!lock_all_vcpus(kvm))
> return -EBUSY;
>
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> if (vcpu->arch.has_run_once) {
> ret = -EBUSY;
> goto out_unlock;
> @@ -266,7 +266,7 @@ int vgic_init(struct kvm *kvm)
> {
> struct vgic_dist *dist = &kvm->arch.vgic;
> struct kvm_vcpu *vcpu;
> - int ret = 0, i;
> + int ret = 0;
>
> if (vgic_initialized(kvm))
> return 0;
> @@ -279,7 +279,7 @@ int vgic_init(struct kvm *kvm)
> if (ret)
> goto out;
>
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> kvm_vgic_vcpu_enable(vcpu);
>
> ret = kvm_vgic_setup_default_irq_routing(kvm);
> @@ -327,13 +327,12 @@ void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
> static void __kvm_vgic_destroy(struct kvm *kvm)
> {
> struct kvm_vcpu *vcpu;
> - int i;
>
> vgic_debug_destroy(kvm);
>
> kvm_vgic_dist_destroy(kvm);
>
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(vcpu, kvm)
> kvm_vgic_vcpu_destroy(vcpu);
> }
>
> diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
> index c5124737c7fc..3c3e865dc98b 100644
> --- a/virt/kvm/arm/vgic/vgic-kvm-device.c
> +++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
> @@ -257,31 +257,33 @@ int vgic_v2_parse_attr(struct kvm_device *dev, struct kvm_device_attr *attr,
> return 0;
> }
>
> -/* unlocks vcpus from @vcpu_lock_idx and smaller */
> -static void unlock_vcpus(struct kvm *kvm, int vcpu_lock_idx)
> +/* unlocks vcpus from up to @last_locked */

from up to ?

I think you mean up to and including.

> +static void unlock_vcpus(struct kvm *kvm, struct kvm_vcpu *last_locked)
> {
> - struct kvm_vcpu *tmp_vcpu;
> + if (last_locked) {
> + struct kvm_vcpu *tmp_vcpu;

That would be more nicely written as
if (!last_locked)
return

kvm_for_each_vcpu(...)

But why not accept a NULL poiner here and call unlock_vcpus from
unlock_all_vcpus ?

>
> - for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
> - tmp_vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
> - mutex_unlock(&tmp_vcpu->mutex);
> + kvm_for_each_vcpu(tmp_vcpu, kvm) {
> + mutex_unlock(&tmp_vcpu->mutex);
> +
> + if (tmp_vcpu == last_locked)
> + return;
> + }
> }
> }
>
> void unlock_all_vcpus(struct kvm *kvm)
> {
> - int i;
> struct kvm_vcpu *tmp_vcpu;
>
> - kvm_for_each_vcpu(i, tmp_vcpu, kvm)
> + kvm_for_each_vcpu(tmp_vcpu, kvm)
> mutex_unlock(&tmp_vcpu->mutex);
> }
>
> /* Returns true if all vcpus were locked, false otherwise */
> bool lock_all_vcpus(struct kvm *kvm)
> {
> - struct kvm_vcpu *tmp_vcpu;
> - int c;
> + struct kvm_vcpu *tmp_vcpu, *last_locked = NULL;
>
> /*
> * Any time a vcpu is run, vcpu_load is called which tries to grab the
> @@ -289,11 +291,13 @@ bool lock_all_vcpus(struct kvm *kvm)
> * that no other VCPUs are run and fiddle with the vgic state while we
> * access it.
> */
> - kvm_for_each_vcpu(c, tmp_vcpu, kvm) {
> + kvm_for_each_vcpu(tmp_vcpu, kvm) {
> if (!mutex_trylock(&tmp_vcpu->mutex)) {
> - unlock_vcpus(kvm, c - 1);
> + unlock_vcpus(kvm, last_locked);

I don't fully understand the split of the patches (which I assume aim
for bisectability) and why unlock_all_vcpus had to be changed in the
previous patch but this call to unlock_vcpus() was allowed to remain
until here?

Thanks,
-Christoffer