Commit 9cb1096f authored by Gavin Shan's avatar Gavin Shan Committed by Marc Zyngier
Browse files

KVM: arm64: Enable ring-based dirty memory tracking 



Enable ring-based dirty memory tracking on ARM64:

  - Enable CONFIG_HAVE_KVM_DIRTY_RING_ACQ_REL.

  - Enable CONFIG_NEED_KVM_DIRTY_RING_WITH_BITMAP.

  - Set KVM_DIRTY_LOG_PAGE_OFFSET for the ring buffer's physical page
    offset.

  - Add ARM64 specific kvm_arch_allow_write_without_running_vcpu() to
    keep the site of saving vgic/its tables out of the no-running-vcpu
    radar.

Signed-off-by: default avatarGavin Shan <gshan@redhat.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221110104914.31280-5-gshan@redhat.com
parent 86bdf3eb

Documentation/virt/kvm/api.rst

+1 −1
Original line number Diff line number Diff line
@@ -7921,7 +7921,7 @@ regardless of what has actually been exposed through the CPUID leaf. 
8.29 KVM_CAP_DIRTY_LOG_RING/KVM_CAP_DIRTY_LOG_RING_ACQ_REL

----------------------------------------------------------



:Architectures: x86

:Architectures: x86, arm64

:Parameters: args[0] - size of the dirty log ring



KVM is capable of tracking dirty memory using ring buffers that are

arch/arm64/include/uapi/asm/kvm.h

+1 −0
Original line number Diff line number Diff line
@@ -43,6 +43,7 @@ 
#define __KVM_HAVE_VCPU_EVENTS



#define KVM_COALESCED_MMIO_PAGE_OFFSET 1

#define KVM_DIRTY_LOG_PAGE_OFFSET 64



#define KVM_REG_SIZE(id)						\

	(1U << (((id) & KVM_REG_SIZE_MASK) >> KVM_REG_SIZE_SHIFT))

arch/arm64/kvm/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -32,6 +32,8 @@ menuconfig KVM 
	select KVM_VFIO

	select HAVE_KVM_EVENTFD

	select HAVE_KVM_IRQFD

	select HAVE_KVM_DIRTY_RING_ACQ_REL

	select NEED_KVM_DIRTY_RING_WITH_BITMAP

	select HAVE_KVM_MSI

	select HAVE_KVM_IRQCHIP

	select HAVE_KVM_IRQ_ROUTING

arch/arm64/kvm/arm.c

+3 −0
Original line number Diff line number Diff line
@@ -746,6 +746,9 @@ static int check_vcpu_requests(struct kvm_vcpu *vcpu) 


		if (kvm_check_request(KVM_REQ_SUSPEND, vcpu))

			return kvm_vcpu_suspend(vcpu);



		if (kvm_dirty_ring_check_request(vcpu))

			return 0;

	}



	return 1;

arch/arm64/kvm/vgic/vgic-its.c

+20 −0
Original line number Diff line number Diff line
@@ -2743,6 +2743,7 @@ static int vgic_its_has_attr(struct kvm_device *dev, 
static int vgic_its_ctrl(struct kvm *kvm, struct vgic_its *its, u64 attr)

{

	const struct vgic_its_abi *abi = vgic_its_get_abi(its);

	struct vgic_dist *dist = &kvm->arch.vgic;

	int ret = 0;



	if (attr == KVM_DEV_ARM_VGIC_CTRL_INIT) /* Nothing to do */
@@ -2762,7 +2763,9 @@ static int vgic_its_ctrl(struct kvm *kvm, struct vgic_its *its, u64 attr) 
		vgic_its_reset(kvm, its);

		break;

	case KVM_DEV_ARM_ITS_SAVE_TABLES:

		dist->save_its_tables_in_progress = true;

		ret = abi->save_tables(its);

		dist->save_its_tables_in_progress = false;

		break;

	case KVM_DEV_ARM_ITS_RESTORE_TABLES:

		ret = abi->restore_tables(its);
@@ -2775,6 +2778,23 @@ static int vgic_its_ctrl(struct kvm *kvm, struct vgic_its *its, u64 attr) 
	return ret;

}



/*

 * kvm_arch_allow_write_without_running_vcpu - allow writing guest memory

 * without the running VCPU when dirty ring is enabled.

 *

 * The running VCPU is required to track dirty guest pages when dirty ring

 * is enabled. Otherwise, the backup bitmap should be used to track the

 * dirty guest pages. When vgic/its tables are being saved, the backup

 * bitmap is used to track the dirty guest pages due to the missed running

 * VCPU in the period.

 */

bool kvm_arch_allow_write_without_running_vcpu(struct kvm *kvm)

{

	struct vgic_dist *dist = &kvm->arch.vgic;



	return dist->save_its_tables_in_progress;

}



static int vgic_its_set_attr(struct kvm_device *dev,

			     struct kvm_device_attr *attr)

{