KVM: PPC: Book3S HV: Run HPT guests on POWER9 radix hosts

[mirror_ubuntu-bionic-kernel.git] / arch / powerpc / kvm / book3s_hv_builtin.c

/*
 * Copyright 2011 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2, as
 * published by the Free Software Foundation.
 */

#include <linux/cpu.h>
#include <linux/kvm_host.h>
#include <linux/preempt.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/memblock.h>
#include <linux/sizes.h>
#include <linux/cma.h>
#include <linux/bitops.h>

#include <asm/cputable.h>
#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>
#include <asm/archrandom.h>
#include <asm/xics.h>
#include <asm/xive.h>
#include <asm/dbell.h>
#include <asm/cputhreads.h>
#include <asm/io.h>
#include <asm/opal.h>
#include <asm/smp.h>

#define KVM_CMA_CHUNK_ORDER     18

#include "book3s_xics.h"
#include "book3s_xive.h"

/*
 * The XIVE module will populate these when it loads
 */
unsigned long (*__xive_vm_h_xirr)(struct kvm_vcpu *vcpu);
unsigned long (*__xive_vm_h_ipoll)(struct kvm_vcpu *vcpu, unsigned long server);
int (*__xive_vm_h_ipi)(struct kvm_vcpu *vcpu, unsigned long server,
                       unsigned long mfrr);
int (*__xive_vm_h_cppr)(struct kvm_vcpu *vcpu, unsigned long cppr);
int (*__xive_vm_h_eoi)(struct kvm_vcpu *vcpu, unsigned long xirr);
EXPORT_SYMBOL_GPL(__xive_vm_h_xirr);
EXPORT_SYMBOL_GPL(__xive_vm_h_ipoll);
EXPORT_SYMBOL_GPL(__xive_vm_h_ipi);
EXPORT_SYMBOL_GPL(__xive_vm_h_cppr);
EXPORT_SYMBOL_GPL(__xive_vm_h_eoi);

/*
 * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
 * should be power of 2.
 */
#define HPT_ALIGN_PAGES         ((1 << 18) >> PAGE_SHIFT) /* 256k */
/*
 * By default we reserve 5% of memory for hash pagetable allocation.
 */
static unsigned long kvm_cma_resv_ratio = 5;

static struct cma *kvm_cma;

static int __init early_parse_kvm_cma_resv(char *p)
{
        pr_debug("%s(%s)\n", __func__, p);
        if (!p)
                return -EINVAL;
        return kstrtoul(p, 0, &kvm_cma_resv_ratio);
}
early_param("kvm_cma_resv_ratio", early_parse_kvm_cma_resv);

struct page *kvm_alloc_hpt_cma(unsigned long nr_pages)
{
        VM_BUG_ON(order_base_2(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);

        return cma_alloc(kvm_cma, nr_pages, order_base_2(HPT_ALIGN_PAGES),
                         GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(kvm_alloc_hpt_cma);

void kvm_free_hpt_cma(struct page *page, unsigned long nr_pages)
{
        cma_release(kvm_cma, page, nr_pages);
}
EXPORT_SYMBOL_GPL(kvm_free_hpt_cma);

/**
 * kvm_cma_reserve() - reserve area for kvm hash pagetable
 *
 * This function reserves memory from early allocator. It should be
 * called by arch specific code once the memblock allocator
 * has been activated and all other subsystems have already allocated/reserved
 * memory.
 */
void __init kvm_cma_reserve(void)
{
        unsigned long align_size;
        struct memblock_region *reg;
        phys_addr_t selected_size = 0;

        /*
         * We need CMA reservation only when we are in HV mode
         */
        if (!cpu_has_feature(CPU_FTR_HVMODE))
                return;
        /*
         * We cannot use memblock_phys_mem_size() here, because
         * memblock_analyze() has not been called yet.
         */
        for_each_memblock(memory, reg)
                selected_size += memblock_region_memory_end_pfn(reg) -
                                 memblock_region_memory_base_pfn(reg);

        selected_size = (selected_size * kvm_cma_resv_ratio / 100) << PAGE_SHIFT;
        if (selected_size) {
                pr_debug("%s: reserving %ld MiB for global area\n", __func__,
                         (unsigned long)selected_size / SZ_1M);
                align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
                cma_declare_contiguous(0, selected_size, 0, align_size,
                        KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, false, "kvm_cma",
                        &kvm_cma);
        }
}

/*
 * Real-mode H_CONFER implementation.
 * We check if we are the only vcpu out of this virtual core
 * still running in the guest and not ceded.  If so, we pop up
 * to the virtual-mode implementation; if not, just return to
 * the guest.
 */
long int kvmppc_rm_h_confer(struct kvm_vcpu *vcpu, int target,
                            unsigned int yield_count)
{
        struct kvmppc_vcore *vc = local_paca->kvm_hstate.kvm_vcore;
        int ptid = local_paca->kvm_hstate.ptid;
        int threads_running;
        int threads_ceded;
        int threads_conferring;
        u64 stop = get_tb() + 10 * tb_ticks_per_usec;
        int rv = H_SUCCESS; /* => don't yield */

        set_bit(ptid, &vc->conferring_threads);
        while ((get_tb() < stop) && !VCORE_IS_EXITING(vc)) {
                threads_running = VCORE_ENTRY_MAP(vc);
                threads_ceded = vc->napping_threads;
                threads_conferring = vc->conferring_threads;
                if ((threads_ceded | threads_conferring) == threads_running) {
                        rv = H_TOO_HARD; /* => do yield */
                        break;
                }
        }
        clear_bit(ptid, &vc->conferring_threads);
        return rv;
}

/*
 * When running HV mode KVM we need to block certain operations while KVM VMs
 * exist in the system. We use a counter of VMs to track this.
 *
 * One of the operations we need to block is onlining of secondaries, so we
 * protect hv_vm_count with get/put_online_cpus().
 */
static atomic_t hv_vm_count;

void kvm_hv_vm_activated(void)
{
        get_online_cpus();
        atomic_inc(&hv_vm_count);
        put_online_cpus();
}
EXPORT_SYMBOL_GPL(kvm_hv_vm_activated);

void kvm_hv_vm_deactivated(void)
{
        get_online_cpus();
        atomic_dec(&hv_vm_count);
        put_online_cpus();
}
EXPORT_SYMBOL_GPL(kvm_hv_vm_deactivated);

bool kvm_hv_mode_active(void)
{
        return atomic_read(&hv_vm_count) != 0;
}

extern int hcall_real_table[], hcall_real_table_end[];

int kvmppc_hcall_impl_hv_realmode(unsigned long cmd)
{
        cmd /= 4;
        if (cmd < hcall_real_table_end - hcall_real_table &&
            hcall_real_table[cmd])
                return 1;

        return 0;
}
EXPORT_SYMBOL_GPL(kvmppc_hcall_impl_hv_realmode);

int kvmppc_hwrng_present(void)
{
        return powernv_hwrng_present();
}
EXPORT_SYMBOL_GPL(kvmppc_hwrng_present);

long kvmppc_h_random(struct kvm_vcpu *vcpu)
{
        int r;

        /* Only need to do the expensive mfmsr() on radix */
        if (kvm_is_radix(vcpu->kvm) && (mfmsr() & MSR_IR))
                r = powernv_get_random_long(&vcpu->arch.gpr[4]);
        else
                r = powernv_get_random_real_mode(&vcpu->arch.gpr[4]);
        if (r)
                return H_SUCCESS;

        return H_HARDWARE;
}

/*
 * Send an interrupt or message to another CPU.
 * The caller needs to include any barrier needed to order writes
 * to memory vs. the IPI/message.
 */
void kvmhv_rm_send_ipi(int cpu)
{
        void __iomem *xics_phys;
        unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER);

        /* On POWER9 we can use msgsnd for any destination cpu. */
        if (cpu_has_feature(CPU_FTR_ARCH_300)) {
                msg |= get_hard_smp_processor_id(cpu);
                __asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg));
                return;
        }

        /* On POWER8 for IPIs to threads in the same core, use msgsnd. */
        if (cpu_has_feature(CPU_FTR_ARCH_207S) &&
            cpu_first_thread_sibling(cpu) ==
            cpu_first_thread_sibling(raw_smp_processor_id())) {
                msg |= cpu_thread_in_core(cpu);
                __asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg));
                return;
        }

        /* We should never reach this */
        if (WARN_ON_ONCE(xive_enabled()))
            return;

        /* Else poke the target with an IPI */
        xics_phys = paca[cpu].kvm_hstate.xics_phys;
        if (xics_phys)
                __raw_rm_writeb(IPI_PRIORITY, xics_phys + XICS_MFRR);
        else
                opal_int_set_mfrr(get_hard_smp_processor_id(cpu), IPI_PRIORITY);
}

/*
 * The following functions are called from the assembly code
 * in book3s_hv_rmhandlers.S.
 */
static void kvmhv_interrupt_vcore(struct kvmppc_vcore *vc, int active)
{
        int cpu = vc->pcpu;

        /* Order setting of exit map vs. msgsnd/IPI */
        smp_mb();
        for (; active; active >>= 1, ++cpu)
                if (active & 1)
                        kvmhv_rm_send_ipi(cpu);
}

void kvmhv_commence_exit(int trap)
{
        struct kvmppc_vcore *vc = local_paca->kvm_hstate.kvm_vcore;
        int ptid = local_paca->kvm_hstate.ptid;
        struct kvm_split_mode *sip = local_paca->kvm_hstate.kvm_split_mode;
        int me, ee, i, t;
        int cpu0;

        /* Set our bit in the threads-exiting-guest map in the 0xff00
           bits of vcore->entry_exit_map */
        me = 0x100 << ptid;
        do {
                ee = vc->entry_exit_map;
        } while (cmpxchg(&vc->entry_exit_map, ee, ee | me) != ee);

        /* Are we the first here? */
        if ((ee >> 8) != 0)
                return;

        /*
         * Trigger the other threads in this vcore to exit the guest.
         * If this is a hypervisor decrementer interrupt then they
         * will be already on their way out of the guest.
         */
        if (trap != BOOK3S_INTERRUPT_HV_DECREMENTER)
                kvmhv_interrupt_vcore(vc, ee & ~(1 << ptid));

        /*
         * If we are doing dynamic micro-threading, interrupt the other
         * subcores to pull them out of their guests too.
         */
        if (!sip)
                return;

        for (i = 0; i < MAX_SUBCORES; ++i) {
                vc = sip->vc[i];
                if (!vc)
                        break;
                do {
                        ee = vc->entry_exit_map;
                        /* Already asked to exit? */
                        if ((ee >> 8) != 0)
                                break;
                } while (cmpxchg(&vc->entry_exit_map, ee,
                                 ee | VCORE_EXIT_REQ) != ee);
                if ((ee >> 8) == 0)
                        kvmhv_interrupt_vcore(vc, ee);
        }

        /*
         * On POWER9 when running a HPT guest on a radix host (sip != NULL),
         * we have to interrupt inactive CPU threads to get them to
         * restore the host LPCR value.
         */
        if (sip->lpcr_req) {
                if (cmpxchg(&sip->do_restore, 0, 1) == 0) {
                        vc = local_paca->kvm_hstate.kvm_vcore;
                        cpu0 = vc->pcpu + ptid - local_paca->kvm_hstate.tid;
                        for (t = 1; t < threads_per_core; ++t) {
                                if (sip->napped[t])
                                        kvmhv_rm_send_ipi(cpu0 + t);
                        }
                }
        }
}

struct kvmppc_host_rm_ops *kvmppc_host_rm_ops_hv;
EXPORT_SYMBOL_GPL(kvmppc_host_rm_ops_hv);

#ifdef CONFIG_KVM_XICS
static struct kvmppc_irq_map *get_irqmap(struct kvmppc_passthru_irqmap *pimap,
                                         u32 xisr)
{
        int i;

        /*
         * We access the mapped array here without a lock.  That
         * is safe because we never reduce the number of entries
         * in the array and we never change the v_hwirq field of
         * an entry once it is set.
         *
         * We have also carefully ordered the stores in the writer
         * and the loads here in the reader, so that if we find a matching
         * hwirq here, the associated GSI and irq_desc fields are valid.
         */
        for (i = 0; i < pimap->n_mapped; i++)  {
                if (xisr == pimap->mapped[i].r_hwirq) {
                        /*
                         * Order subsequent reads in the caller to serialize
                         * with the writer.
                         */
                        smp_rmb();
                        return &pimap->mapped[i];
                }
        }
        return NULL;
}

/*
 * If we have an interrupt that's not an IPI, check if we have a
 * passthrough adapter and if so, check if this external interrupt
 * is for the adapter.
 * We will attempt to deliver the IRQ directly to the target VCPU's
 * ICP, the virtual ICP (based on affinity - the xive value in ICS).
 *
 * If the delivery fails or if this is not for a passthrough adapter,
 * return to the host to handle this interrupt. We earlier
 * saved a copy of the XIRR in the PACA, it will be picked up by
 * the host ICP driver.
 */
static int kvmppc_check_passthru(u32 xisr, __be32 xirr, bool *again)
{
        struct kvmppc_passthru_irqmap *pimap;
        struct kvmppc_irq_map *irq_map;
        struct kvm_vcpu *vcpu;

        vcpu = local_paca->kvm_hstate.kvm_vcpu;
        if (!vcpu)
                return 1;
        pimap = kvmppc_get_passthru_irqmap(vcpu->kvm);
        if (!pimap)
                return 1;
        irq_map = get_irqmap(pimap, xisr);
        if (!irq_map)
                return 1;

        /* We're handling this interrupt, generic code doesn't need to */
        local_paca->kvm_hstate.saved_xirr = 0;

        return kvmppc_deliver_irq_passthru(vcpu, xirr, irq_map, pimap, again);
}

#else
static inline int kvmppc_check_passthru(u32 xisr, __be32 xirr, bool *again)
{
        return 1;
}
#endif

/*
 * Determine what sort of external interrupt is pending (if any).
 * Returns:
 *      0 if no interrupt is pending
 *      1 if an interrupt is pending that needs to be handled by the host
 *      2 Passthrough that needs completion in the host
 *      -1 if there was a guest wakeup IPI (which has now been cleared)
 *      -2 if there is PCI passthrough external interrupt that was handled
 */
static long kvmppc_read_one_intr(bool *again);

long kvmppc_read_intr(void)
{
        long ret = 0;
        long rc;
        bool again;

        if (xive_enabled())
                return 1;

        do {
                again = false;
                rc = kvmppc_read_one_intr(&again);
                if (rc && (ret == 0 || rc > ret))
                        ret = rc;
        } while (again);
        return ret;
}

static long kvmppc_read_one_intr(bool *again)
{
        void __iomem *xics_phys;
        u32 h_xirr;
        __be32 xirr;
        u32 xisr;
        u8 host_ipi;
        int64_t rc;

        if (xive_enabled())
                return 1;

        /* see if a host IPI is pending */
        host_ipi = local_paca->kvm_hstate.host_ipi;
        if (host_ipi)
                return 1;

        /* Now read the interrupt from the ICP */
        xics_phys = local_paca->kvm_hstate.xics_phys;
        rc = 0;
        if (!xics_phys)
                rc = opal_int_get_xirr(&xirr, false);
        else
                xirr = __raw_rm_readl(xics_phys + XICS_XIRR);
        if (rc < 0)
                return 1;

        /*
         * Save XIRR for later. Since we get control in reverse endian
         * on LE systems, save it byte reversed and fetch it back in
         * host endian. Note that xirr is the value read from the
         * XIRR register, while h_xirr is the host endian version.
         */
        h_xirr = be32_to_cpu(xirr);
        local_paca->kvm_hstate.saved_xirr = h_xirr;
        xisr = h_xirr & 0xffffff;
        /*
         * Ensure that the store/load complete to guarantee all side
         * effects of loading from XIRR has completed
         */
        smp_mb();

        /* if nothing pending in the ICP */
        if (!xisr)
                return 0;

        /* We found something in the ICP...
         *
         * If it is an IPI, clear the MFRR and EOI it.
         */
        if (xisr == XICS_IPI) {
                rc = 0;
                if (xics_phys) {
                        __raw_rm_writeb(0xff, xics_phys + XICS_MFRR);
                        __raw_rm_writel(xirr, xics_phys + XICS_XIRR);
                } else {
                        opal_int_set_mfrr(hard_smp_processor_id(), 0xff);
                        rc = opal_int_eoi(h_xirr);
                }
                /* If rc > 0, there is another interrupt pending */
                *again = rc > 0;

                /*
                 * Need to ensure side effects of above stores
                 * complete before proceeding.
                 */
                smp_mb();

                /*
                 * We need to re-check host IPI now in case it got set in the
                 * meantime. If it's clear, we bounce the interrupt to the
                 * guest
                 */
                host_ipi = local_paca->kvm_hstate.host_ipi;
                if (unlikely(host_ipi != 0)) {
                        /* We raced with the host,
                         * we need to resend that IPI, bummer
                         */
                        if (xics_phys)
                                __raw_rm_writeb(IPI_PRIORITY,
                                                xics_phys + XICS_MFRR);
                        else
                                opal_int_set_mfrr(hard_smp_processor_id(),
                                                  IPI_PRIORITY);
                        /* Let side effects complete */
                        smp_mb();
                        return 1;
                }

                /* OK, it's an IPI for us */
                local_paca->kvm_hstate.saved_xirr = 0;
                return -1;
        }

        return kvmppc_check_passthru(xisr, xirr, again);
}

#ifdef CONFIG_KVM_XICS
static inline bool is_rm(void)
{
        return !(mfmsr() & MSR_DR);
}

unsigned long kvmppc_rm_h_xirr(struct kvm_vcpu *vcpu)
{
        if (!kvmppc_xics_enabled(vcpu))
                return H_TOO_HARD;
        if (xive_enabled()) {
                if (is_rm())
                        return xive_rm_h_xirr(vcpu);
                if (unlikely(!__xive_vm_h_xirr))
                        return H_NOT_AVAILABLE;
                return __xive_vm_h_xirr(vcpu);
        } else
                return xics_rm_h_xirr(vcpu);
}

unsigned long kvmppc_rm_h_xirr_x(struct kvm_vcpu *vcpu)
{
        if (!kvmppc_xics_enabled(vcpu))
                return H_TOO_HARD;
        vcpu->arch.gpr[5] = get_tb();
        if (xive_enabled()) {
                if (is_rm())
                        return xive_rm_h_xirr(vcpu);
                if (unlikely(!__xive_vm_h_xirr))
                        return H_NOT_AVAILABLE;
                return __xive_vm_h_xirr(vcpu);
        } else
                return xics_rm_h_xirr(vcpu);
}

unsigned long kvmppc_rm_h_ipoll(struct kvm_vcpu *vcpu, unsigned long server)
{
        if (!kvmppc_xics_enabled(vcpu))
                return H_TOO_HARD;
        if (xive_enabled()) {
                if (is_rm())
                        return xive_rm_h_ipoll(vcpu, server);
                if (unlikely(!__xive_vm_h_ipoll))
                        return H_NOT_AVAILABLE;
                return __xive_vm_h_ipoll(vcpu, server);
        } else
                return H_TOO_HARD;
}

int kvmppc_rm_h_ipi(struct kvm_vcpu *vcpu, unsigned long server,
                    unsigned long mfrr)
{
        if (!kvmppc_xics_enabled(vcpu))
                return H_TOO_HARD;
        if (xive_enabled()) {
                if (is_rm())
                        return xive_rm_h_ipi(vcpu, server, mfrr);
                if (unlikely(!__xive_vm_h_ipi))
                        return H_NOT_AVAILABLE;
                return __xive_vm_h_ipi(vcpu, server, mfrr);
        } else
                return xics_rm_h_ipi(vcpu, server, mfrr);
}

int kvmppc_rm_h_cppr(struct kvm_vcpu *vcpu, unsigned long cppr)
{
        if (!kvmppc_xics_enabled(vcpu))
                return H_TOO_HARD;
        if (xive_enabled()) {
                if (is_rm())
                        return xive_rm_h_cppr(vcpu, cppr);
                if (unlikely(!__xive_vm_h_cppr))
                        return H_NOT_AVAILABLE;
                return __xive_vm_h_cppr(vcpu, cppr);
        } else
                return xics_rm_h_cppr(vcpu, cppr);
}

int kvmppc_rm_h_eoi(struct kvm_vcpu *vcpu, unsigned long xirr)
{
        if (!kvmppc_xics_enabled(vcpu))
                return H_TOO_HARD;
        if (xive_enabled()) {
                if (is_rm())
                        return xive_rm_h_eoi(vcpu, xirr);
                if (unlikely(!__xive_vm_h_eoi))
                        return H_NOT_AVAILABLE;
                return __xive_vm_h_eoi(vcpu, xirr);
        } else
                return xics_rm_h_eoi(vcpu, xirr);
}
#endif /* CONFIG_KVM_XICS */

void kvmppc_bad_interrupt(struct pt_regs *regs)
{
        die("Bad interrupt in KVM entry/exit code", regs, SIGABRT);
        panic("Bad KVM trap");
}

/*
 * Functions used to switch LPCR HR and UPRT bits on all threads
 * when entering and exiting HPT guests on a radix host.
 */

#define PHASE_REALMODE          1       /* in real mode */
#define PHASE_SET_LPCR          2       /* have set LPCR */
#define PHASE_OUT_OF_GUEST      4       /* have finished executing in guest */
#define PHASE_RESET_LPCR        8       /* have reset LPCR to host value */

#define ALL(p)          (((p) << 24) | ((p) << 16) | ((p) << 8) | (p))

static void wait_for_sync(struct kvm_split_mode *sip, int phase)
{
        int thr = local_paca->kvm_hstate.tid;

        sip->lpcr_sync.phase[thr] |= phase;
        phase = ALL(phase);
        while ((sip->lpcr_sync.allphases & phase) != phase) {
                HMT_low();
                barrier();
        }
        HMT_medium();
}

void kvmhv_p9_set_lpcr(struct kvm_split_mode *sip)
{
        unsigned long rb, set;

        /* wait for every other thread to get to real mode */
        wait_for_sync(sip, PHASE_REALMODE);

        /* Set LPCR and LPIDR */
        mtspr(SPRN_LPCR, sip->lpcr_req);
        mtspr(SPRN_LPID, sip->lpidr_req);
        isync();

        /* Invalidate the TLB on thread 0 */
        if (local_paca->kvm_hstate.tid == 0) {
                sip->do_set = 0;
                asm volatile("ptesync" : : : "memory");
                for (set = 0; set < POWER9_TLB_SETS_RADIX; ++set) {
                        rb = TLBIEL_INVAL_SET_LPID +
                                (set << TLBIEL_INVAL_SET_SHIFT);
                        asm volatile(PPC_TLBIEL(%0, %1, 0, 0, 0) : :
                                     "r" (rb), "r" (0));
                }
                asm volatile("ptesync" : : : "memory");
        }

        /* indicate that we have done so and wait for others */
        wait_for_sync(sip, PHASE_SET_LPCR);
        /* order read of sip->lpcr_sync.allphases vs. sip->do_set */
        smp_rmb();
}

/*
 * Called when a thread that has been in the guest needs
 * to reload the host LPCR value - but only on POWER9 when
 * running a HPT guest on a radix host.
 */
void kvmhv_p9_restore_lpcr(struct kvm_split_mode *sip)
{
        /* we're out of the guest... */
        wait_for_sync(sip, PHASE_OUT_OF_GUEST);

        mtspr(SPRN_LPID, 0);
        mtspr(SPRN_LPCR, sip->host_lpcr);
        isync();

        if (local_paca->kvm_hstate.tid == 0) {
                sip->do_restore = 0;
                smp_wmb();      /* order store of do_restore vs. phase */
        }

        wait_for_sync(sip, PHASE_RESET_LPCR);
        smp_mb();
        local_paca->kvm_hstate.kvm_split_mode = NULL;
}