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author | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-13 20:55:09 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-13 20:55:09 +0300 |
commit | b9085bcbf5f43adf60533f9b635b2e7faeed0fe9 (patch) | |
tree | e397abf5682a45c096e75b3d0fa99c8e228425fc /virt/kvm/kvm_main.c | |
parent | c7d7b98671552abade78834c522b7308bda73c0d (diff) | |
parent | 6557bada461afeaa920a189fae2cff7c8fdce39f (diff) | |
download | linux-b9085bcbf5f43adf60533f9b635b2e7faeed0fe9.tar.xz |
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM update from Paolo Bonzini:
"Fairly small update, but there are some interesting new features.
Common:
Optional support for adding a small amount of polling on each HLT
instruction executed in the guest (or equivalent for other
architectures). This can improve latency up to 50% on some
scenarios (e.g. O_DSYNC writes or TCP_RR netperf tests). This
also has to be enabled manually for now, but the plan is to
auto-tune this in the future.
ARM/ARM64:
The highlights are support for GICv3 emulation and dirty page
tracking
s390:
Several optimizations and bugfixes. Also a first: a feature
exposed by KVM (UUID and long guest name in /proc/sysinfo) before
it is available in IBM's hypervisor! :)
MIPS:
Bugfixes.
x86:
Support for PML (page modification logging, a new feature in
Broadwell Xeons that speeds up dirty page tracking), nested
virtualization improvements (nested APICv---a nice optimization),
usual round of emulation fixes.
There is also a new option to reduce latency of the TSC deadline
timer in the guest; this needs to be tuned manually.
Some commits are common between this pull and Catalin's; I see you
have already included his tree.
Powerpc:
Nothing yet.
The KVM/PPC changes will come in through the PPC maintainers,
because I haven't received them yet and I might end up being
offline for some part of next week"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (130 commits)
KVM: ia64: drop kvm.h from installed user headers
KVM: x86: fix build with !CONFIG_SMP
KVM: x86: emulate: correct page fault error code for NoWrite instructions
KVM: Disable compat ioctl for s390
KVM: s390: add cpu model support
KVM: s390: use facilities and cpu_id per KVM
KVM: s390/CPACF: Choose crypto control block format
s390/kernel: Update /proc/sysinfo file with Extended Name and UUID
KVM: s390: reenable LPP facility
KVM: s390: floating irqs: fix user triggerable endless loop
kvm: add halt_poll_ns module parameter
kvm: remove KVM_MMIO_SIZE
KVM: MIPS: Don't leak FPU/DSP to guest
KVM: MIPS: Disable HTW while in guest
KVM: nVMX: Enable nested posted interrupt processing
KVM: nVMX: Enable nested virtual interrupt delivery
KVM: nVMX: Enable nested apic register virtualization
KVM: nVMX: Make nested control MSRs per-cpu
KVM: nVMX: Enable nested virtualize x2apic mode
KVM: nVMX: Prepare for using hardware MSR bitmap
...
Diffstat (limited to 'virt/kvm/kvm_main.c')
-rw-r--r-- | virt/kvm/kvm_main.c | 144 |
1 files changed, 131 insertions, 13 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 458b9b14b15c..a1093700f3a4 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -66,6 +66,9 @@ MODULE_AUTHOR("Qumranet"); MODULE_LICENSE("GPL"); +unsigned int halt_poll_ns = 0; +module_param(halt_poll_ns, uint, S_IRUGO | S_IWUSR); + /* * Ordering of locks: * @@ -89,7 +92,7 @@ struct dentry *kvm_debugfs_dir; static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl, unsigned long arg); -#ifdef CONFIG_COMPAT +#ifdef CONFIG_KVM_COMPAT static long kvm_vcpu_compat_ioctl(struct file *file, unsigned int ioctl, unsigned long arg); #endif @@ -176,6 +179,7 @@ bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req) return called; } +#ifndef CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL void kvm_flush_remote_tlbs(struct kvm *kvm) { long dirty_count = kvm->tlbs_dirty; @@ -186,6 +190,7 @@ void kvm_flush_remote_tlbs(struct kvm *kvm) cmpxchg(&kvm->tlbs_dirty, dirty_count, 0); } EXPORT_SYMBOL_GPL(kvm_flush_remote_tlbs); +#endif void kvm_reload_remote_mmus(struct kvm *kvm) { @@ -673,6 +678,7 @@ static void update_memslots(struct kvm_memslots *slots, if (!new->npages) { WARN_ON(!mslots[i].npages); new->base_gfn = 0; + new->flags = 0; if (mslots[i].npages) slots->used_slots--; } else { @@ -993,6 +999,86 @@ out: } EXPORT_SYMBOL_GPL(kvm_get_dirty_log); +#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT +/** + * kvm_get_dirty_log_protect - get a snapshot of dirty pages, and if any pages + * are dirty write protect them for next write. + * @kvm: pointer to kvm instance + * @log: slot id and address to which we copy the log + * @is_dirty: flag set if any page is dirty + * + * We need to keep it in mind that VCPU threads can write to the bitmap + * concurrently. So, to avoid losing track of dirty pages we keep the + * following order: + * + * 1. Take a snapshot of the bit and clear it if needed. + * 2. Write protect the corresponding page. + * 3. Copy the snapshot to the userspace. + * 4. Upon return caller flushes TLB's if needed. + * + * Between 2 and 4, the guest may write to the page using the remaining TLB + * entry. This is not a problem because the page is reported dirty using + * the snapshot taken before and step 4 ensures that writes done after + * exiting to userspace will be logged for the next call. + * + */ +int kvm_get_dirty_log_protect(struct kvm *kvm, + struct kvm_dirty_log *log, bool *is_dirty) +{ + struct kvm_memory_slot *memslot; + int r, i; + unsigned long n; + unsigned long *dirty_bitmap; + unsigned long *dirty_bitmap_buffer; + + r = -EINVAL; + if (log->slot >= KVM_USER_MEM_SLOTS) + goto out; + + memslot = id_to_memslot(kvm->memslots, log->slot); + + dirty_bitmap = memslot->dirty_bitmap; + r = -ENOENT; + if (!dirty_bitmap) + goto out; + + n = kvm_dirty_bitmap_bytes(memslot); + + dirty_bitmap_buffer = dirty_bitmap + n / sizeof(long); + memset(dirty_bitmap_buffer, 0, n); + + spin_lock(&kvm->mmu_lock); + *is_dirty = false; + for (i = 0; i < n / sizeof(long); i++) { + unsigned long mask; + gfn_t offset; + + if (!dirty_bitmap[i]) + continue; + + *is_dirty = true; + + mask = xchg(&dirty_bitmap[i], 0); + dirty_bitmap_buffer[i] = mask; + + offset = i * BITS_PER_LONG; + kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot, offset, + mask); + } + + spin_unlock(&kvm->mmu_lock); + + r = -EFAULT; + if (copy_to_user(log->dirty_bitmap, dirty_bitmap_buffer, n)) + goto out; + + r = 0; +out: + return r; +} +EXPORT_SYMBOL_GPL(kvm_get_dirty_log_protect); +#endif + bool kvm_largepages_enabled(void) { return largepages_enabled; @@ -1551,6 +1637,7 @@ int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data, } return 0; } +EXPORT_SYMBOL_GPL(kvm_write_guest); int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc, gpa_t gpa, unsigned long len) @@ -1687,29 +1774,60 @@ void mark_page_dirty(struct kvm *kvm, gfn_t gfn) } EXPORT_SYMBOL_GPL(mark_page_dirty); +static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu) +{ + if (kvm_arch_vcpu_runnable(vcpu)) { + kvm_make_request(KVM_REQ_UNHALT, vcpu); + return -EINTR; + } + if (kvm_cpu_has_pending_timer(vcpu)) + return -EINTR; + if (signal_pending(current)) + return -EINTR; + + return 0; +} + /* * The vCPU has executed a HLT instruction with in-kernel mode enabled. */ void kvm_vcpu_block(struct kvm_vcpu *vcpu) { + ktime_t start, cur; DEFINE_WAIT(wait); + bool waited = false; + + start = cur = ktime_get(); + if (halt_poll_ns) { + ktime_t stop = ktime_add_ns(ktime_get(), halt_poll_ns); + do { + /* + * This sets KVM_REQ_UNHALT if an interrupt + * arrives. + */ + if (kvm_vcpu_check_block(vcpu) < 0) { + ++vcpu->stat.halt_successful_poll; + goto out; + } + cur = ktime_get(); + } while (single_task_running() && ktime_before(cur, stop)); + } for (;;) { prepare_to_wait(&vcpu->wq, &wait, TASK_INTERRUPTIBLE); - if (kvm_arch_vcpu_runnable(vcpu)) { - kvm_make_request(KVM_REQ_UNHALT, vcpu); - break; - } - if (kvm_cpu_has_pending_timer(vcpu)) - break; - if (signal_pending(current)) + if (kvm_vcpu_check_block(vcpu) < 0) break; + waited = true; schedule(); } finish_wait(&vcpu->wq, &wait); + cur = ktime_get(); + +out: + trace_kvm_vcpu_wakeup(ktime_to_ns(cur) - ktime_to_ns(start), waited); } EXPORT_SYMBOL_GPL(kvm_vcpu_block); @@ -1892,7 +2010,7 @@ static int kvm_vcpu_release(struct inode *inode, struct file *filp) static struct file_operations kvm_vcpu_fops = { .release = kvm_vcpu_release, .unlocked_ioctl = kvm_vcpu_ioctl, -#ifdef CONFIG_COMPAT +#ifdef CONFIG_KVM_COMPAT .compat_ioctl = kvm_vcpu_compat_ioctl, #endif .mmap = kvm_vcpu_mmap, @@ -2182,7 +2300,7 @@ out: return r; } -#ifdef CONFIG_COMPAT +#ifdef CONFIG_KVM_COMPAT static long kvm_vcpu_compat_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) { @@ -2274,7 +2392,7 @@ static int kvm_device_release(struct inode *inode, struct file *filp) static const struct file_operations kvm_device_fops = { .unlocked_ioctl = kvm_device_ioctl, -#ifdef CONFIG_COMPAT +#ifdef CONFIG_KVM_COMPAT .compat_ioctl = kvm_device_ioctl, #endif .release = kvm_device_release, @@ -2561,7 +2679,7 @@ out: return r; } -#ifdef CONFIG_COMPAT +#ifdef CONFIG_KVM_COMPAT struct compat_kvm_dirty_log { __u32 slot; __u32 padding1; @@ -2608,7 +2726,7 @@ out: static struct file_operations kvm_vm_fops = { .release = kvm_vm_release, .unlocked_ioctl = kvm_vm_ioctl, -#ifdef CONFIG_COMPAT +#ifdef CONFIG_KVM_COMPAT .compat_ioctl = kvm_vm_compat_ioctl, #endif .llseek = noop_llseek, |