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Commit 5ea11f2b authored by Suravee Suthikulpanit's avatar Suravee Suthikulpanit Committed by Paolo Bonzini
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svm: Introduces AVIC per-VM ID 



Introduces per-VM AVIC ID and helper functions to manage the IDs.
Currently, the ID will be used to implement 32-bit AVIC IOMMU GA tag.

The ID is 24-bit one-based indexing value, and is managed via helper
functions to get the next ID, or to free an ID once a VM is destroyed.
There should be no ID conflict for any active VMs.

Reviewed-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: default avatarSuravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 9ac7e3e8

arch/x86/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -781,6 +781,7 @@ struct kvm_arch { 
	bool disabled_lapic_found;



	/* Struct members for AVIC */

	u32 avic_vm_id;

	u32 ldr_mode;

	struct page *avic_logical_id_table_page;

	struct page *avic_physical_id_table_page;

arch/x86/kvm/svm.c

+51 −0
Original line number Diff line number Diff line
@@ -96,6 +96,19 @@ MODULE_DEVICE_TABLE(x86cpu, svm_cpu_id); 
#define AVIC_UNACCEL_ACCESS_OFFSET_MASK		0xFF0

#define AVIC_UNACCEL_ACCESS_VECTOR_MASK		0xFFFFFFFF



/* AVIC GATAG is encoded using VM and VCPU IDs */

#define AVIC_VCPU_ID_BITS		8

#define AVIC_VCPU_ID_MASK		((1 << AVIC_VCPU_ID_BITS) - 1)



#define AVIC_VM_ID_BITS			24

#define AVIC_VM_ID_NR			(1 << AVIC_VM_ID_BITS)

#define AVIC_VM_ID_MASK			((1 << AVIC_VM_ID_BITS) - 1)



#define AVIC_GATAG(x, y)		(((x & AVIC_VM_ID_MASK) << AVIC_VCPU_ID_BITS) | \

						(y & AVIC_VCPU_ID_MASK))

#define AVIC_GATAG_TO_VMID(x)		((x >> AVIC_VCPU_ID_BITS) & AVIC_VM_ID_MASK)

#define AVIC_GATAG_TO_VCPUID(x)		(x & AVIC_VCPU_ID_MASK)



static bool erratum_383_found __read_mostly;



static const u32 host_save_user_msrs[] = {
@@ -242,6 +255,10 @@ static int avic; 
module_param(avic, int, S_IRUGO);

#endif



/* AVIC VM ID bit masks and lock */

static DECLARE_BITMAP(avic_vm_id_bitmap, AVIC_VM_ID_NR);

static DEFINE_SPINLOCK(avic_vm_id_lock);



static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0);

static void svm_flush_tlb(struct kvm_vcpu *vcpu);

static void svm_complete_interrupts(struct vcpu_svm *svm);
@@ -1280,10 +1297,40 @@ static int avic_init_backing_page(struct kvm_vcpu *vcpu) 
	return 0;

}



static inline int avic_get_next_vm_id(void)

{

	int id;



	spin_lock(&avic_vm_id_lock);



	/* AVIC VM ID is one-based. */

	id = find_next_zero_bit(avic_vm_id_bitmap, AVIC_VM_ID_NR, 1);

	if (id <= AVIC_VM_ID_MASK)

		__set_bit(id, avic_vm_id_bitmap);

	else

		id = -EAGAIN;



	spin_unlock(&avic_vm_id_lock);

	return id;

}



static inline int avic_free_vm_id(int id)

{

	if (id <= 0 || id > AVIC_VM_ID_MASK)

		return -EINVAL;



	spin_lock(&avic_vm_id_lock);

	__clear_bit(id, avic_vm_id_bitmap);

	spin_unlock(&avic_vm_id_lock);

	return 0;

}



static void avic_vm_destroy(struct kvm *kvm)

{

	struct kvm_arch *vm_data = &kvm->arch;



	avic_free_vm_id(vm_data->avic_vm_id);



	if (vm_data->avic_logical_id_table_page)

		__free_page(vm_data->avic_logical_id_table_page);

	if (vm_data->avic_physical_id_table_page)
@@ -1300,6 +1347,10 @@ static int avic_vm_init(struct kvm *kvm) 
	if (!avic)

		return 0;



	vm_data->avic_vm_id = avic_get_next_vm_id();

	if (vm_data->avic_vm_id < 0)

		return vm_data->avic_vm_id;



	/* Allocating physical APIC ID table (4KB) */

	p_page = alloc_page(GFP_KERNEL);

	if (!p_page)