linux-kernel - [PATCH v4 13/18] KVM: x86/tdp_mmu: Propagate attr

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20240718211230.1492011-14-rick.p.edgecombe@intel.com>
Date: Thu, 18 Jul 2024 14:12:25 -0700
From: Rick Edgecombe <rick.p.edgecombe@...el.com>
To: seanjc@...gle.com,
	pbonzini@...hat.com,
	kvm@...r.kernel.org
Cc: kai.huang@...el.com,
	dmatlack@...gle.com,
	erdemaktas@...gle.com,
	isaku.yamahata@...il.com,
	linux-kernel@...r.kernel.org,
	sagis@...gle.com,
	yan.y.zhao@...el.com,
	rick.p.edgecombe@...el.com,
	Isaku Yamahata <isaku.yamahata@...el.com>
Subject: [PATCH v4 13/18] KVM: x86/tdp_mmu: Propagate attr_filter to MMU notifier callbacks

From: Isaku Yamahata <isaku.yamahata@...el.com>

Teach the MMU notifier callbacks how to check kvm_gfn_range.process to
filter which KVM MMU root types to operate on.

The private GPAs are backed by guest memfd. Such memory is not subjected
to MMU notifier callbacks because it can't be mapped into the host user
address space. Now kvm_gfn_range conveys info about which root to operate
on. Enhance the callback to filter the root page table type.

The KVM MMU notifier comes down to two functions.
kvm_tdp_mmu_unmap_gfn_range() and kvm_tdp_mmu_handle_gfn().

For VM's without a private/shared split in the EPT, all operations
should target the normal(direct) root.

invalidate_range_start() comes into kvm_tdp_mmu_unmap_gfn_range().
invalidate_range_end() doesn't come into arch code.

With the switch from for_each_tdp_mmu_root() to
__for_each_tdp_mmu_root() in kvm_tdp_mmu_handle_gfn(), there are no
longer any users of for_each_tdp_mmu_root(). Remove it.

Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@...el.com>
---
v3:
 - Change subject from "Make mmu notifier callbacks to check
   kvm_process" to "Propagate attr_filter to MMU notifier callbacks"
   (Paolo)
 - Remove no longer used for_each_tdp_mmu_root() (Binbin)

v2:
 - Use newly added kvm_process_to_root_types()

v1:
 - Remove warning (Rick)
 - Remove confusing mention of mapping flags (Chao)
 - Re-write coverletter
---
 arch/x86/kvm/mmu/tdp_mmu.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 5af7355ef015..748fdacc719c 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -193,9 +193,6 @@ static struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm,
 		     !tdp_mmu_root_match((_root), (_types)))) {			\
 		} else
 
-#define for_each_tdp_mmu_root(_kvm, _root, _as_id)			\
-	__for_each_tdp_mmu_root(_kvm, _root, _as_id, KVM_ALL_ROOTS)
-
 #define for_each_valid_tdp_mmu_root(_kvm, _root, _as_id)		\
 	__for_each_tdp_mmu_root(_kvm, _root, _as_id, KVM_VALID_ROOTS)
 
@@ -1214,12 +1211,16 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 	return ret;
 }
 
+/* Used by mmu notifier via kvm_unmap_gfn_range() */
 bool kvm_tdp_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range,
 				 bool flush)
 {
+	enum kvm_tdp_mmu_root_types types;
 	struct kvm_mmu_page *root;
 
-	__for_each_tdp_mmu_root_yield_safe(kvm, root, range->slot->as_id, KVM_ALL_ROOTS)
+	types = kvm_gfn_range_filter_to_root_types(kvm, range->attr_filter);
+
+	__for_each_tdp_mmu_root_yield_safe(kvm, root, range->slot->as_id, types)
 		flush = tdp_mmu_zap_leafs(kvm, root, range->start, range->end,
 					  range->may_block, flush);
 
@@ -1233,15 +1234,18 @@ static __always_inline bool kvm_tdp_mmu_handle_gfn(struct kvm *kvm,
 						   struct kvm_gfn_range *range,
 						   tdp_handler_t handler)
 {
+	enum kvm_tdp_mmu_root_types types;
 	struct kvm_mmu_page *root;
 	struct tdp_iter iter;
 	bool ret = false;
 
+	types = kvm_gfn_range_filter_to_root_types(kvm, range->attr_filter);
+
 	/*
 	 * Don't support rescheduling, none of the MMU notifiers that funnel
 	 * into this helper allow blocking; it'd be dead, wasteful code.
 	 */
-	for_each_tdp_mmu_root(kvm, root, range->slot->as_id) {
+	__for_each_tdp_mmu_root(kvm, root, range->slot->as_id, types) {
 		rcu_read_lock();
 
 		tdp_root_for_each_leaf_pte(iter, kvm, root, range->start, range->end)
-- 
2.34.1