Commit c3a62df4 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

Merge branch kvm-arm64/pgtable-fixes-6.4 into kvmarm-master/fixes 



* kvm-arm64/pgtable-fixes-6.4:
  : .
  : Fixes for concurrent S2 mapping race from Oliver:
  :
  : "So it appears that there is a race between two parallel stage-2 map
  : walkers that could lead to mapping the incorrect PA for a given IPA, as
  : the IPA -> PA relationship picks up an unintended offset. This series
  : eliminates the problem by using the current IPA of the walk as the
  : source-of-truth regarding where we are in a map operation."
  : .
  KVM: arm64: Constify start/end/phys fields of the pgtable walker data
  KVM: arm64: Infer PA offset from VA in hyp map walker
  KVM: arm64: Infer the PA offset from IPA in stage-2 map walker

Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parents 9a48c597 1ea24415

arch/arm64/include/asm/kvm_pgtable.h

+1 −0
Original line number Diff line number Diff line
@@ -209,6 +209,7 @@ struct kvm_pgtable_visit_ctx { 
	kvm_pte_t				old;

	void					*arg;

	struct kvm_pgtable_mm_ops		*mm_ops;

	u64					start;

	u64					addr;

	u64					end;

	u32					level;

arch/arm64/kvm/hyp/pgtable.c

+32 −9
Original line number Diff line number Diff line
@@ -58,8 +58,9 @@ 
struct kvm_pgtable_walk_data {

	struct kvm_pgtable_walker	*walker;



	const u64			start;

	u64				addr;

	u64				end;

	const u64			end;

};



static bool kvm_phys_is_valid(u64 phys)
@@ -201,6 +202,7 @@ static inline int __kvm_pgtable_visit(struct kvm_pgtable_walk_data *data, 
		.old	= READ_ONCE(*ptep),

		.arg	= data->walker->arg,

		.mm_ops	= mm_ops,

		.start	= data->start,

		.addr	= data->addr,

		.end	= data->end,

		.level	= level,
@@ -293,6 +295,7 @@ int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size, 
		     struct kvm_pgtable_walker *walker)

{

	struct kvm_pgtable_walk_data walk_data = {

		.start	= ALIGN_DOWN(addr, PAGE_SIZE),

		.addr	= ALIGN_DOWN(addr, PAGE_SIZE),

		.end	= PAGE_ALIGN(walk_data.addr + size),

		.walker	= walker,
@@ -349,7 +352,7 @@ int kvm_pgtable_get_leaf(struct kvm_pgtable *pgt, u64 addr, 
}



struct hyp_map_data {

	u64				phys;

	const u64			phys;

	kvm_pte_t			attr;

};
@@ -407,13 +410,12 @@ enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte) 
static bool hyp_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx,

				    struct hyp_map_data *data)

{

	u64 phys = data->phys + (ctx->addr - ctx->start);

	kvm_pte_t new;

	u64 granule = kvm_granule_size(ctx->level), phys = data->phys;



	if (!kvm_block_mapping_supported(ctx, phys))

		return false;



	data->phys += granule;

	new = kvm_init_valid_leaf_pte(phys, data->attr, ctx->level);

	if (ctx->old == new)

		return true;
@@ -576,7 +578,7 @@ void kvm_pgtable_hyp_destroy(struct kvm_pgtable *pgt) 
}



struct stage2_map_data {

	u64				phys;

	const u64			phys;

	kvm_pte_t			attr;

	u8				owner_id;
@@ -794,20 +796,43 @@ static bool stage2_pte_executable(kvm_pte_t pte) 
	return !(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN);

}



static u64 stage2_map_walker_phys_addr(const struct kvm_pgtable_visit_ctx *ctx,

				       const struct stage2_map_data *data)

{

	u64 phys = data->phys;



	/*

	 * Stage-2 walks to update ownership data are communicated to the map

	 * walker using an invalid PA. Avoid offsetting an already invalid PA,

	 * which could overflow and make the address valid again.

	 */

	if (!kvm_phys_is_valid(phys))

		return phys;



	/*

	 * Otherwise, work out the correct PA based on how far the walk has

	 * gotten.

	 */

	return phys + (ctx->addr - ctx->start);

}



static bool stage2_leaf_mapping_allowed(const struct kvm_pgtable_visit_ctx *ctx,

					struct stage2_map_data *data)

{

	u64 phys = stage2_map_walker_phys_addr(ctx, data);



	if (data->force_pte && (ctx->level < (KVM_PGTABLE_MAX_LEVELS - 1)))

		return false;



	return kvm_block_mapping_supported(ctx, data->phys);

	return kvm_block_mapping_supported(ctx, phys);

}



static int stage2_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx,

				      struct stage2_map_data *data)

{

	kvm_pte_t new;

	u64 granule = kvm_granule_size(ctx->level), phys = data->phys;

	u64 phys = stage2_map_walker_phys_addr(ctx, data);

	u64 granule = kvm_granule_size(ctx->level);

	struct kvm_pgtable *pgt = data->mmu->pgt;

	struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
@@ -841,8 +866,6 @@ static int stage2_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx, 


	stage2_make_pte(ctx, new);



	if (kvm_phys_is_valid(phys))

		data->phys += granule;

	return 0;

}