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KVM: Introduce KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2

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The previous KVM_CAP_MANUAL_DIRTY_LOG_PROTECT has some problem which
blocks the correct usage from userspace.  Obsolete the old one and
introduce a new capability bit for it.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Peter Xu 2019-05-08 17:15:47 +08:00 committed by Paolo Bonzini
parent 53eac7a8f8
commit d7547c55cb
4 changed files with 17 additions and 11 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

15
Documentation/virtual/kvm/api.txt
View file

@ -330,7 +330,7 @@ They must be less than the value that KVM_CHECK_EXTENSION returns for
the KVM_CAP_MULTI_ADDRESS_SPACE capability.
The bits in the dirty bitmap are cleared before the ioctl returns, unless
KVM_CAP_MANUAL_DIRTY_LOG_PROTECT is enabled. For more information,
KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is enabled. For more information,
see the description of the capability.
4.9 KVM_SET_MEMORY_ALIAS
@ -3791,7 +3791,7 @@ to I/O ports.
4.117 KVM_CLEAR_DIRTY_LOG (vm ioctl)
Capability: KVM_CAP_MANUAL_DIRTY_LOG_PROTECT
Capability: KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2
Architectures: x86
Type: vm ioctl
Parameters: struct kvm_dirty_log (in)
@ -3824,10 +3824,10 @@ the address space for which you want to return the dirty bitmap.
They must be less than the value that KVM_CHECK_EXTENSION returns for
the KVM_CAP_MULTI_ADDRESS_SPACE capability.
This ioctl is mostly useful when KVM_CAP_MANUAL_DIRTY_LOG_PROTECT
This ioctl is mostly useful when KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2
is enabled; for more information, see the description of the capability.
However, it can always be used as long as KVM_CHECK_EXTENSION confirms
that KVM_CAP_MANUAL_DIRTY_LOG_PROTECT is present.
that KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is present.
4.118 KVM_GET_SUPPORTED_HV_CPUID
@ -4780,7 +4780,7 @@ and injected exceptions.
* For the new DR6 bits, note that bit 16 is set iff the #DB exception
will clear DR6.RTM.
7.18 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT
7.18 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2
Architectures: all
Parameters: args[0] whether feature should be enabled or not
@ -4803,6 +4803,11 @@ while userspace can see false reports of dirty pages. Manual reprotection
helps reducing this time, improving guest performance and reducing the
number of dirty log false positives.
KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 was previously available under the name
KVM_CAP_MANUAL_DIRTY_LOG_PROTECT, but the implementation had bugs that make
it hard or impossible to use it correctly. The availability of
KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 signals that those bugs are fixed.
Userspace should not try to use KVM_CAP_MANUAL_DIRTY_LOG_PROTECT.
8. Other capabilities.
----------------------

5
include/uapi/linux/kvm.h
View file

@ -986,8 +986,9 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_HYPERV_ENLIGHTENED_VMCS 163
#define KVM_CAP_EXCEPTION_PAYLOAD 164
#define KVM_CAP_ARM_VM_IPA_SIZE 165
#define KVM_CAP_MANUAL_DIRTY_LOG_PROTECT 166
#define KVM_CAP_MANUAL_DIRTY_LOG_PROTECT 166 /* Obsolete */
#define KVM_CAP_HYPERV_CPUID 167
#define KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 168
#ifdef KVM_CAP_IRQ_ROUTING
@ -1434,7 +1435,7 @@ struct kvm_enc_region {
#define KVM_GET_NESTED_STATE _IOWR(KVMIO, 0xbe, struct kvm_nested_state)
#define KVM_SET_NESTED_STATE _IOW(KVMIO, 0xbf, struct kvm_nested_state)
/* Available with KVM_CAP_MANUAL_DIRTY_LOG_PROTECT */
/* Available with KVM_CAP_MANUAL_DIRTY_LOG_PROTECT_2 */
#define KVM_CLEAR_DIRTY_LOG _IOWR(KVMIO, 0xc0, struct kvm_clear_dirty_log)
/* Available with KVM_CAP_HYPERV_CPUID */

4
tools/testing/selftests/kvm/dirty_log_test.c
View file

@ -311,7 +311,7 @@ static void run_test(enum vm_guest_mode mode, unsigned long iterations,
#ifdef USE_CLEAR_DIRTY_LOG
struct kvm_enable_cap cap = {};
cap.cap = KVM_CAP_MANUAL_DIRTY_LOG_PROTECT;
cap.cap = KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2;
cap.args[0] = 1;
vm_enable_cap(vm, &cap);
#endif
@ -427,7 +427,7 @@ int main(int argc, char *argv[])
int opt, i;
#ifdef USE_CLEAR_DIRTY_LOG
if (!kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT)) {
if (!kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2)) {
fprintf(stderr, "KVM_CLEAR_DIRTY_LOG not available, skipping tests\n");
exit(KSFT_SKIP);
}

4
virt/kvm/kvm_main.c
View file

@ -3110,7 +3110,7 @@ static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
case KVM_CAP_CHECK_EXTENSION_VM:
case KVM_CAP_ENABLE_CAP_VM:
#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
case KVM_CAP_MANUAL_DIRTY_LOG_PROTECT:
case KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2:
#endif
return 1;
#ifdef CONFIG_KVM_MMIO
@ -3148,7 +3148,7 @@ static int kvm_vm_ioctl_enable_cap_generic(struct kvm *kvm,
{
switch (cap->cap) {
#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
case KVM_CAP_MANUAL_DIRTY_LOG_PROTECT:
case KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2:
if (cap->flags || (cap->args[0] & ~1))
return -EINVAL;
kvm->manual_dirty_log_protect = cap->args[0];