diff options
Diffstat (limited to 'arch/x86/kernel/kvm.c')
| -rw-r--r-- | arch/x86/kernel/kvm.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c new file mode 100644 index 000000000000..8b7a3cf37d2b --- /dev/null +++ b/arch/x86/kernel/kvm.c @@ -0,0 +1,248 @@ +/* + * KVM paravirt_ops implementation + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo@redhat.com> + * Copyright IBM Corporation, 2007 + * Authors: Anthony Liguori <aliguori@us.ibm.com> + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/kvm_para.h> +#include <linux/cpu.h> +#include <linux/mm.h> +#include <linux/highmem.h> +#include <linux/hardirq.h> + +#define MMU_QUEUE_SIZE 1024 + +struct kvm_para_state { + u8 mmu_queue[MMU_QUEUE_SIZE]; + int mmu_queue_len; + enum paravirt_lazy_mode mode; +}; + +static DEFINE_PER_CPU(struct kvm_para_state, para_state); + +static struct kvm_para_state *kvm_para_state(void) +{ + return &per_cpu(para_state, raw_smp_processor_id()); +} + +/* + * No need for any "IO delay" on KVM + */ +static void kvm_io_delay(void) +{ +} + +static void kvm_mmu_op(void *buffer, unsigned len) +{ + int r; + unsigned long a1, a2; + + do { + a1 = __pa(buffer); + a2 = 0; /* on i386 __pa() always returns <4G */ + r = kvm_hypercall3(KVM_HC_MMU_OP, len, a1, a2); + buffer += r; + len -= r; + } while (len); +} + +static void mmu_queue_flush(struct kvm_para_state *state) +{ + if (state->mmu_queue_len) { + kvm_mmu_op(state->mmu_queue, state->mmu_queue_len); + state->mmu_queue_len = 0; + } +} + +static void kvm_deferred_mmu_op(void *buffer, int len) +{ + struct kvm_para_state *state = kvm_para_state(); + + if (state->mode != PARAVIRT_LAZY_MMU) { + kvm_mmu_op(buffer, len); + return; + } + if (state->mmu_queue_len + len > sizeof state->mmu_queue) + mmu_queue_flush(state); + memcpy(state->mmu_queue + state->mmu_queue_len, buffer, len); + state->mmu_queue_len += len; +} + +static void kvm_mmu_write(void *dest, u64 val) +{ + __u64 pte_phys; + struct kvm_mmu_op_write_pte wpte; + +#ifdef CONFIG_HIGHPTE + struct page *page; + unsigned long dst = (unsigned long) dest; + + page = kmap_atomic_to_page(dest); + pte_phys = page_to_pfn(page); + pte_phys <<= PAGE_SHIFT; + pte_phys += (dst & ~(PAGE_MASK)); +#else + pte_phys = (unsigned long)__pa(dest); +#endif + wpte.header.op = KVM_MMU_OP_WRITE_PTE; + wpte.pte_val = val; + wpte.pte_phys = pte_phys; + + kvm_deferred_mmu_op(&wpte, sizeof wpte); +} + +/* + * We only need to hook operations that are MMU writes. We hook these so that + * we can use lazy MMU mode to batch these operations. We could probably + * improve the performance of the host code if we used some of the information + * here to simplify processing of batched writes. + */ +static void kvm_set_pte(pte_t *ptep, pte_t pte) +{ + kvm_mmu_write(ptep, pte_val(pte)); +} + +static void kvm_set_pte_at(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, pte_t pte) +{ + kvm_mmu_write(ptep, pte_val(pte)); +} + +static void kvm_set_pmd(pmd_t *pmdp, pmd_t pmd) +{ + kvm_mmu_write(pmdp, pmd_val(pmd)); +} + +#if PAGETABLE_LEVELS >= 3 +#ifdef CONFIG_X86_PAE +static void kvm_set_pte_atomic(pte_t *ptep, pte_t pte) +{ + kvm_mmu_write(ptep, pte_val(pte)); +} + +static void kvm_set_pte_present(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, pte_t pte) +{ + kvm_mmu_write(ptep, pte_val(pte)); +} + +static void kvm_pte_clear(struct mm_struct *mm, + unsigned long addr, pte_t *ptep) +{ + kvm_mmu_write(ptep, 0); +} + +static void kvm_pmd_clear(pmd_t *pmdp) +{ + kvm_mmu_write(pmdp, 0); +} +#endif + +static void kvm_set_pud(pud_t *pudp, pud_t pud) +{ + kvm_mmu_write(pudp, pud_val(pud)); +} + +#if PAGETABLE_LEVELS == 4 +static void kvm_set_pgd(pgd_t *pgdp, pgd_t pgd) +{ + kvm_mmu_write(pgdp, pgd_val(pgd)); +} +#endif +#endif /* PAGETABLE_LEVELS >= 3 */ + +static void kvm_flush_tlb(void) +{ + struct kvm_mmu_op_flush_tlb ftlb = { + .header.op = KVM_MMU_OP_FLUSH_TLB, + }; + + kvm_deferred_mmu_op(&ftlb, sizeof ftlb); +} + +static void kvm_release_pt(u32 pfn) +{ + struct kvm_mmu_op_release_pt rpt = { + .header.op = KVM_MMU_OP_RELEASE_PT, + .pt_phys = (u64)pfn << PAGE_SHIFT, + }; + + kvm_mmu_op(&rpt, sizeof rpt); +} + +static void kvm_enter_lazy_mmu(void) +{ + struct kvm_para_state *state = kvm_para_state(); + + paravirt_enter_lazy_mmu(); + state->mode = paravirt_get_lazy_mode(); +} + +static void kvm_leave_lazy_mmu(void) +{ + struct kvm_para_state *state = kvm_para_state(); + + mmu_queue_flush(state); + paravirt_leave_lazy(paravirt_get_lazy_mode()); + state->mode = paravirt_get_lazy_mode(); +} + +static void paravirt_ops_setup(void) +{ + pv_info.name = "KVM"; + pv_info.paravirt_enabled = 1; + + if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY)) + pv_cpu_ops.io_delay = kvm_io_delay; + + if (kvm_para_has_feature(KVM_FEATURE_MMU_OP)) { + pv_mmu_ops.set_pte = kvm_set_pte; + pv_mmu_ops.set_pte_at = kvm_set_pte_at; + pv_mmu_ops.set_pmd = kvm_set_pmd; +#if PAGETABLE_LEVELS >= 3 +#ifdef CONFIG_X86_PAE + pv_mmu_ops.set_pte_atomic = kvm_set_pte_atomic; + pv_mmu_ops.set_pte_present = kvm_set_pte_present; + pv_mmu_ops.pte_clear = kvm_pte_clear; + pv_mmu_ops.pmd_clear = kvm_pmd_clear; +#endif + pv_mmu_ops.set_pud = kvm_set_pud; +#if PAGETABLE_LEVELS == 4 + pv_mmu_ops.set_pgd = kvm_set_pgd; +#endif +#endif + pv_mmu_ops.flush_tlb_user = kvm_flush_tlb; + pv_mmu_ops.release_pte = kvm_release_pt; + pv_mmu_ops.release_pmd = kvm_release_pt; + pv_mmu_ops.release_pud = kvm_release_pt; + + pv_mmu_ops.lazy_mode.enter = kvm_enter_lazy_mmu; + pv_mmu_ops.lazy_mode.leave = kvm_leave_lazy_mmu; + } +} + +void __init kvm_guest_init(void) +{ + if (!kvm_para_available()) + return; + + paravirt_ops_setup(); +} |