Commit 5af3e9d0 authored by Paul Mackerras's avatar Paul Mackerras
Browse files

KVM: PPC: Book3S HV: Flush guest mappings when turning dirty tracking on/off 



This adds code to flush the partition-scoped page tables for a radix
guest when dirty tracking is turned on or off for a memslot.  Only the
guest real addresses covered by the memslot are flushed.  The reason
for this is to get rid of any 2M PTEs in the partition-scoped page
tables that correspond to host transparent huge pages, so that page
dirtiness is tracked at a system page (4k or 64k) granularity rather
than a 2M granularity.  The page tables are also flushed when turning
dirty tracking off so that the memslot's address space can be
repopulated with THPs if possible.

To do this, we add a new function kvmppc_radix_flush_memslot().  Since
this does what's needed for kvmppc_core_flush_memslot_hv() on a radix
guest, we now make kvmppc_core_flush_memslot_hv() call the new
kvmppc_radix_flush_memslot() rather than calling kvm_unmap_radix()
for each page in the memslot.  This has the effect of fixing a bug in
that kvmppc_core_flush_memslot_hv() was previously calling
kvm_unmap_radix() without holding the kvm->mmu_lock spinlock, which
is required to be held.

Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
Reviewed-by: default avatarSuraj Jitindar Singh <sjitindarsingh@gmail.com>
Reviewed-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
parent c43c3a86

arch/powerpc/include/asm/kvm_book3s.h

+2 −0
Original line number Diff line number Diff line
@@ -222,6 +222,8 @@ extern int kvm_test_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot, 
			unsigned long gfn);

extern long kvmppc_hv_get_dirty_log_radix(struct kvm *kvm,

			struct kvm_memory_slot *memslot, unsigned long *map);

extern void kvmppc_radix_flush_memslot(struct kvm *kvm,

			const struct kvm_memory_slot *memslot);

extern int kvmhv_get_rmmu_info(struct kvm *kvm, struct kvm_ppc_rmmu_info *info);



/* XXX remove this export when load_last_inst() is generic */

arch/powerpc/kvm/book3s_64_mmu_hv.c

+5 −4
Original line number Diff line number Diff line
@@ -899,11 +899,12 @@ void kvmppc_core_flush_memslot_hv(struct kvm *kvm, 


	gfn = memslot->base_gfn;

	rmapp = memslot->arch.rmap;

	for (n = memslot->npages; n; --n, ++gfn) {

	if (kvm_is_radix(kvm)) {

			kvm_unmap_radix(kvm, memslot, gfn);

			continue;

		kvmppc_radix_flush_memslot(kvm, memslot);

		return;

	}



	for (n = memslot->npages; n; --n, ++gfn) {

		/*

		 * Testing the present bit without locking is OK because

		 * the memslot has been marked invalid already, and hence

arch/powerpc/kvm/book3s_64_mmu_radix.c

+20 −0
Original line number Diff line number Diff line
@@ -958,6 +958,26 @@ long kvmppc_hv_get_dirty_log_radix(struct kvm *kvm, 
	return 0;

}



void kvmppc_radix_flush_memslot(struct kvm *kvm,

				const struct kvm_memory_slot *memslot)

{

	unsigned long n;

	pte_t *ptep;

	unsigned long gpa;

	unsigned int shift;



	gpa = memslot->base_gfn << PAGE_SHIFT;

	spin_lock(&kvm->mmu_lock);

	for (n = memslot->npages; n; --n) {

		ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);

		if (ptep && pte_present(*ptep))

			kvmppc_unmap_pte(kvm, ptep, gpa, shift, memslot,

					 kvm->arch.lpid);

		gpa += PAGE_SIZE;

	}

	spin_unlock(&kvm->mmu_lock);

}



static void add_rmmu_ap_encoding(struct kvm_ppc_rmmu_info *info,

				 int psize, int *indexp)

{

arch/powerpc/kvm/book3s_hv.c

+17 −0
Original line number Diff line number Diff line
@@ -4384,6 +4384,23 @@ static void kvmppc_core_commit_memory_region_hv(struct kvm *kvm, 
	 */

	if (npages)

		atomic64_inc(&kvm->arch.mmio_update);



	/*

	 * For change == KVM_MR_MOVE or KVM_MR_DELETE, higher levels

	 * have already called kvm_arch_flush_shadow_memslot() to

	 * flush shadow mappings.  For KVM_MR_CREATE we have no

	 * previous mappings.  So the only case to handle is

	 * KVM_MR_FLAGS_ONLY when the KVM_MEM_LOG_DIRTY_PAGES bit

	 * has been changed.

	 * For radix guests, we flush on setting KVM_MEM_LOG_DIRTY_PAGES

	 * to get rid of any THP PTEs in the partition-scoped page tables

	 * so we can track dirtiness at the page level; we flush when

	 * clearing KVM_MEM_LOG_DIRTY_PAGES so that we can go back to

	 * using THP PTEs.

	 */

	if (change == KVM_MR_FLAGS_ONLY && kvm_is_radix(kvm) &&

	    ((new->flags ^ old->flags) & KVM_MEM_LOG_DIRTY_PAGES))

		kvmppc_radix_flush_memslot(kvm, old);

}



/*

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