Commit bc6678a3 authored by Marcelo Tosatti's avatar Marcelo Tosatti
Browse files

KVM: introduce kvm->srcu and convert kvm_set_memory_region to SRCU update 



Use two steps for memslot deletion: mark the slot invalid (which stops
instantiation of new shadow pages for that slot, but allows destruction),
then instantiate the new empty slot.

Also simplifies kvm_handle_hva locking.

Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 3ad26d81

arch/ia64/kvm/kvm-ia64.c

+3 −1
Original line number Diff line number Diff line
@@ -1382,7 +1382,7 @@ static void kvm_release_vm_pages(struct kvm *kvm) 
	int i, j;

	unsigned long base_gfn;



	slots = kvm->memslots;

	slots = rcu_dereference(kvm->memslots);

	for (i = 0; i < slots->nmemslots; i++) {

		memslot = &slots->memslots[i];

		base_gfn = memslot->base_gfn;
@@ -1837,6 +1837,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, 
	struct kvm_memory_slot *memslot;

	int is_dirty = 0;



	down_write(&kvm->slots_lock);

	spin_lock(&kvm->arch.dirty_log_lock);



	r = kvm_ia64_sync_dirty_log(kvm, log);
@@ -1856,6 +1857,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, 
	}

	r = 0;

out:

	up_write(&kvm->slots_lock);

	spin_unlock(&kvm->arch.dirty_log_lock);

	return r;

}

arch/x86/kvm/mmu.c

+14 −14
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <linux/swap.h>

#include <linux/hugetlb.h>

#include <linux/compiler.h>

#include <linux/srcu.h>



#include <asm/page.h>

#include <asm/cmpxchg.h>
@@ -807,21 +808,15 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long hva, 
{

	int i, j;

	int retval = 0;

	struct kvm_memslots *slots = kvm->memslots;

	struct kvm_memslots *slots;



	slots = rcu_dereference(kvm->memslots);



	/*

	 * If mmap_sem isn't taken, we can look the memslots with only

	 * the mmu_lock by skipping over the slots with userspace_addr == 0.

	 */

	for (i = 0; i < slots->nmemslots; i++) {

		struct kvm_memory_slot *memslot = &slots->memslots[i];

		unsigned long start = memslot->userspace_addr;

		unsigned long end;



		/* mmu_lock protects userspace_addr */

		if (!start)

			continue;



		end = start + (memslot->npages << PAGE_SHIFT);

		if (hva >= start && hva < end) {

			gfn_t gfn_offset = (hva - start) >> PAGE_SHIFT;
@@ -1617,7 +1612,7 @@ static void mmu_unshadow(struct kvm *kvm, gfn_t gfn) 


static void page_header_update_slot(struct kvm *kvm, void *pte, gfn_t gfn)

{

	int slot = memslot_id(kvm, gfn_to_memslot(kvm, gfn));

	int slot = memslot_id(kvm, gfn);

	struct kvm_mmu_page *sp = page_header(__pa(pte));



	__set_bit(slot, sp->slot_bitmap);
@@ -3021,9 +3016,11 @@ unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm) 
	int i;

	unsigned int nr_mmu_pages;

	unsigned int  nr_pages = 0;

	struct kvm_memslots *slots;



	for (i = 0; i < kvm->memslots->nmemslots; i++)

		nr_pages += kvm->memslots->memslots[i].npages;

	slots = rcu_dereference(kvm->memslots);

	for (i = 0; i < slots->nmemslots; i++)

		nr_pages += slots->memslots[i].npages;



	nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;

	nr_mmu_pages = max(nr_mmu_pages,
@@ -3293,10 +3290,12 @@ static void audit_mappings(struct kvm_vcpu *vcpu) 
static int count_rmaps(struct kvm_vcpu *vcpu)

{

	int nmaps = 0;

	int i, j, k;

	int i, j, k, idx;



	idx = srcu_read_lock(&kvm->srcu);

	slots = rcu_dereference(kvm->memslots);

	for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {

		struct kvm_memory_slot *m = &vcpu->kvm->memslots->memslots[i];

		struct kvm_memory_slot *m = &slots->memslots[i];

		struct kvm_rmap_desc *d;



		for (j = 0; j < m->npages; ++j) {
@@ -3319,6 +3318,7 @@ static int count_rmaps(struct kvm_vcpu *vcpu) 
			}

		}

	}

	srcu_read_unlock(&kvm->srcu, idx);

	return nmaps;

}

arch/x86/kvm/vmx.c

+5 −1
Original line number Diff line number Diff line
@@ -1503,7 +1503,11 @@ static void enter_pmode(struct kvm_vcpu *vcpu) 
static gva_t rmode_tss_base(struct kvm *kvm)

{

	if (!kvm->arch.tss_addr) {

		gfn_t base_gfn = kvm->memslots->memslots[0].base_gfn +

		struct kvm_memslots *slots;

		gfn_t base_gfn;



		slots = rcu_dereference(kvm->memslots);

		base_gfn = kvm->memslots->memslots[0].base_gfn +

				 kvm->memslots->memslots[0].npages - 3;

		return base_gfn << PAGE_SHIFT;

	}

include/linux/kvm.h

+1 −1
Original line number Diff line number Diff line
@@ -103,7 +103,7 @@ struct kvm_userspace_memory_region { 


/* for kvm_memory_region::flags */

#define KVM_MEM_LOG_DIRTY_PAGES  1UL



#define KVM_MEMSLOT_INVALID      (1UL << 1)



/* for KVM_IRQ_LINE */

struct kvm_irq_level {

include/linux/kvm_host.h

+2 −5
Original line number Diff line number Diff line
@@ -162,6 +162,7 @@ struct kvm { 
	struct rw_semaphore slots_lock;

	struct mm_struct *mm; /* userspace tied to this vm */

	struct kvm_memslots *memslots;

	struct srcu_struct srcu;

#ifdef CONFIG_KVM_APIC_ARCHITECTURE

	u32 bsp_vcpu_id;

	struct kvm_vcpu *bsp_vcpu;
@@ -275,6 +276,7 @@ void kvm_set_page_accessed(struct page *page); 
pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn);

pfn_t gfn_to_pfn_memslot(struct kvm *kvm,

			 struct kvm_memory_slot *slot, gfn_t gfn);

int memslot_id(struct kvm *kvm, gfn_t gfn);

void kvm_release_pfn_dirty(pfn_t);

void kvm_release_pfn_clean(pfn_t pfn);

void kvm_set_pfn_dirty(pfn_t pfn);
@@ -490,11 +492,6 @@ static inline void kvm_guest_exit(void) 
	current->flags &= ~PF_VCPU;

}



static inline int memslot_id(struct kvm *kvm, struct kvm_memory_slot *slot)

{

	return slot - kvm->memslots->memslots;

}



static inline gpa_t gfn_to_gpa(gfn_t gfn)

{

	return (gpa_t)gfn << PAGE_SHIFT;

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