KVM: Portability: split kvm_vcpu_ioctl

This patch splits kvm_vcpu_ioctl into archtecture independent parts, and
x86 specific parts which go to kvm_arch_vcpu_ioctl in x86.c.

Common ioctls for all architectures are:
KVM_RUN, KVM_GET/SET_(S-)REGS, KVM_TRANSLATE, KVM_INTERRUPT,
KVM_DEBUG_GUEST, KVM_SET_SIGNAL_MASK, KVM_GET/SET_FPU
Note that some PPC chips don't have an FPU, so we might need an #ifdef
around KVM_GET/SET_FPU one day.

x86 specific ioctls are:
KVM_GET/SET_LAPIC, KVM_SET_CPUID, KVM_GET/SET_MSRS

An interresting aspect is vcpu_load/vcpu_put. We now have a common
vcpu_load/put which does the preemption stuff, and an architecture
specific kvm_arch_vcpu_load/put. In the x86 case, this one calls the
vmx/svm function defined in kvm_x86_ops.

Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 219 insertions, 0 deletions

diff --git a/drivers/kvm/x86.c b/drivers/kvm/x86.c
index 437902cf178..1fe209dd4ca 100644
--- a/drivers/kvm/x86.c
+++ b/drivers/kvm/x86.c
@@ -14,10 +14,18 @@
  *
  */
 
+#include "kvm.h"
 #include "x86.h"
+#include "irq.h"
+
+#include <linux/kvm.h>
+#include <linux/fs.h>
+#include <linux/vmalloc.h>
 
 #include <asm/uaccess.h>
 
+#define MAX_IO_MSRS 256
+
 /*
  * List of msr numbers which we expose to userspace through KVM_GET_MSRS
  * and KVM_SET_MSRS, and KVM_GET_MSR_INDEX_LIST.
@@ -40,6 +48,86 @@ static u32 emulated_msrs[] = {
         MSR_IA32_MISC_ENABLE,
 };
 
+/*
+ * Adapt set_msr() to msr_io()'s calling convention
+ */
+static int do_set_msr(struct kvm_vcpu *vcpu, unsigned index, u64 *data)
+{
+        return kvm_set_msr(vcpu, index, *data);
+}
+
+/*
+ * Read or write a bunch of msrs. All parameters are kernel addresses.
+ *
+ * @return number of msrs set successfully.
+ */
+static int __msr_io(struct kvm_vcpu *vcpu, struct kvm_msrs *msrs,
+                    struct kvm_msr_entry *entries,
+                    int (*do_msr)(struct kvm_vcpu *vcpu,
+                                  unsigned index, u64 *data))
+{
+        int i;
+
+        vcpu_load(vcpu);
+
+        for (i = 0; i < msrs->nmsrs; ++i)
+                if (do_msr(vcpu, entries[i].index, &entries[i].data))
+                        break;
+
+        vcpu_put(vcpu);
+
+        return i;
+}
+
+/*
+ * Read or write a bunch of msrs. Parameters are user addresses.
+ *
+ * @return number of msrs set successfully.
+ */
+static int msr_io(struct kvm_vcpu *vcpu, struct kvm_msrs __user *user_msrs,
+                  int (*do_msr)(struct kvm_vcpu *vcpu,
+                                unsigned index, u64 *data),
+                  int writeback)
+{
+        struct kvm_msrs msrs;
+        struct kvm_msr_entry *entries;
+        int r, n;
+        unsigned size;
+
+        r = -EFAULT;
+        if (copy_from_user(&msrs, user_msrs, sizeof msrs))
+                goto out;
+
+        r = -E2BIG;
+        if (msrs.nmsrs >= MAX_IO_MSRS)
+                goto out;
+
+        r = -ENOMEM;
+        size = sizeof(struct kvm_msr_entry) * msrs.nmsrs;
+        entries = vmalloc(size);
+        if (!entries)
+                goto out;
+
+        r = -EFAULT;
+        if (copy_from_user(entries, user_msrs->entries, size))
+                goto out_free;
+
+        r = n = __msr_io(vcpu, &msrs, entries, do_msr);
+        if (r < 0)
+                goto out_free;
+
+        r = -EFAULT;
+        if (writeback && copy_to_user(user_msrs->entries, entries, size))
+                goto out_free;
+
+        r = n;
+
+out_free:
+        vfree(entries);
+out:
+        return r;
+}
+
 long kvm_arch_dev_ioctl(struct file *filp,
                         unsigned int ioctl, unsigned long arg)
 {
@@ -81,6 +169,137 @@ out:
         return r;
 }
 
+void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
+{
+        kvm_x86_ops->vcpu_load(vcpu, cpu);
+}
+
+void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
+{
+        kvm_x86_ops->vcpu_put(vcpu);
+}
+
+static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu)
+{
+        u64 efer;
+        int i;
+        struct kvm_cpuid_entry *e, *entry;
+
+        rdmsrl(MSR_EFER, efer);
+        entry = NULL;
+        for (i = 0; i < vcpu->cpuid_nent; ++i) {
+                e = &vcpu->cpuid_entries[i];
+                if (e->function == 0x80000001) {
+                        entry = e;
+                        break;
+                }
+        }
+        if (entry && (entry->edx & (1 << 20)) && !(efer & EFER_NX)) {
+                entry->edx &= ~(1 << 20);
+                printk(KERN_INFO "kvm: guest NX capability removed\n");
+        }
+}
+
+static int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
+                                    struct kvm_cpuid *cpuid,
+                                    struct kvm_cpuid_entry __user *entries)
+{
+        int r;
+
+        r = -E2BIG;
+        if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
+                goto out;
+        r = -EFAULT;
+        if (copy_from_user(&vcpu->cpuid_entries, entries,
+                           cpuid->nent * sizeof(struct kvm_cpuid_entry)))
+                goto out;
+        vcpu->cpuid_nent = cpuid->nent;
+        cpuid_fix_nx_cap(vcpu);
+        return 0;
+
+out:
+        return r;
+}
+
+static int kvm_vcpu_ioctl_get_lapic(struct kvm_vcpu *vcpu,
+                                    struct kvm_lapic_state *s)
+{
+        vcpu_load(vcpu);
+        memcpy(s->regs, vcpu->apic->regs, sizeof *s);
+        vcpu_put(vcpu);
+
+        return 0;
+}
+
+static int kvm_vcpu_ioctl_set_lapic(struct kvm_vcpu *vcpu,
+                                    struct kvm_lapic_state *s)
+{
+        vcpu_load(vcpu);
+        memcpy(vcpu->apic->regs, s->regs, sizeof *s);
+        kvm_apic_post_state_restore(vcpu);
+        vcpu_put(vcpu);
+
+        return 0;
+}
+
+long kvm_arch_vcpu_ioctl(struct file *filp,
+                         unsigned int ioctl, unsigned long arg)
+{
+        struct kvm_vcpu *vcpu = filp->private_data;
+        void __user *argp = (void __user *)arg;
+        int r;
+
+        switch (ioctl) {
+        case KVM_GET_LAPIC: {
+                struct kvm_lapic_state lapic;
+
+                memset(&lapic, 0, sizeof lapic);
+                r = kvm_vcpu_ioctl_get_lapic(vcpu, &lapic);
+                if (r)
+                        goto out;
+                r = -EFAULT;
+                if (copy_to_user(argp, &lapic, sizeof lapic))
+                        goto out;
+                r = 0;
+                break;
+        }
+        case KVM_SET_LAPIC: {
+                struct kvm_lapic_state lapic;
+
+                r = -EFAULT;
+                if (copy_from_user(&lapic, argp, sizeof lapic))
+                        goto out;
+                r = kvm_vcpu_ioctl_set_lapic(vcpu, &lapic);;
+                if (r)
+                        goto out;
+                r = 0;
+                break;
+        }
+        case KVM_SET_CPUID: {
+                struct kvm_cpuid __user *cpuid_arg = argp;
+                struct kvm_cpuid cpuid;
+
+                r = -EFAULT;
+                if (copy_from_user(&cpuid, cpuid_arg, sizeof cpuid))
+                        goto out;
+                r = kvm_vcpu_ioctl_set_cpuid(vcpu, &cpuid, cpuid_arg->entries);
+                if (r)
+                        goto out;
+                break;
+        }
+        case KVM_GET_MSRS:
+                r = msr_io(vcpu, argp, kvm_get_msr, 1);
+                break;
+        case KVM_SET_MSRS:
+                r = msr_io(vcpu, argp, do_set_msr, 0);
+                break;
+        default:
+                r = -EINVAL;
+        }
+out:
+        return r;
+}
+
 static __init void kvm_init_msr_list(void)
 {
         u32 dummy[2];