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();
+}