arch/powerpc/kvm/book3s_hv_builtin.c - kernel/bruno - Git at Google

 /*
  * 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/dbell.h>
 #include <asm/cputhreads.h>

 #define KVM_CMA_CHUNK_ORDER	18

 /*
  * 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(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));
 }
 EXPORT_SYMBOL_GPL(kvm_alloc_hpt);

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

 /**
  * 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);
 	}
 }

 /*
  * 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)
 {
 	if (powernv_get_random_real_mode(&vcpu->arch.gpr[4]))
 		return H_SUCCESS;

 	return H_HARDWARE;
 }

 static inline void rm_writeb(unsigned long paddr, u8 val)
 {
 	__asm__ __volatile__("stbcix %0,0,%1"
 		: : "r" (val), "r" (paddr) : "memory");
 }

 /*
  * Send an interrupt or message to another CPU.
  * This can only be called in real mode.
  * The caller needs to include any barrier needed to order writes
  * to memory vs. the IPI/message.
  */
 void kvmhv_rm_send_ipi(int cpu)
 {
 	unsigned long xics_phys;

 	/* 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())) {
 		unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER);
 		msg |= cpu_thread_in_core(cpu);
 		__asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg));
 		return;
 	}

 	/* Else poke the target with an IPI */
 	xics_phys = paca[cpu].kvm_hstate.xics_phys;
 	rm_writeb(xics_phys + XICS_MFRR, 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;

 	/* 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->master_vcs[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);
 	}
 }
	/*
	* 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/dbell.h>
	#include <asm/cputhreads.h>

	#define KVM_CMA_CHUNK_ORDER 18

	/*
	* 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(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));
	}
	EXPORT_SYMBOL_GPL(kvm_alloc_hpt);

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

	/**
	* 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);
	}
	}

	/*
	* 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)
	{
	if (powernv_get_random_real_mode(&vcpu->arch.gpr[4]))
	return H_SUCCESS;

	return H_HARDWARE;
	}

	static inline void rm_writeb(unsigned long paddr, u8 val)
	{
	__asm__ __volatile__("stbcix %0,0,%1"
	: : "r" (val), "r" (paddr) : "memory");
	}

	/*
	* Send an interrupt or message to another CPU.
	* This can only be called in real mode.
	* The caller needs to include any barrier needed to order writes
	* to memory vs. the IPI/message.
	*/
	void kvmhv_rm_send_ipi(int cpu)
	{
	unsigned long xics_phys;

	/* 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())) {
	unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER);
	msg \|= cpu_thread_in_core(cpu);
	__asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg));
	return;
	}

	/* Else poke the target with an IPI */
	xics_phys = paca[cpu].kvm_hstate.xics_phys;
	rm_writeb(xics_phys + XICS_MFRR, 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;

	/* 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->master_vcs[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);
	}
	}