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Reply-To: Sean Christopherson <seanjc@google.com>
Date:   Wed, 13 Sep 2023 18:54:59 -0700
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Subject: [RFC PATCH v12 01/33] KVM: Tweak kvm_hva_range and hva_handler_t to
 allow reusing for gfn ranges
From:   Sean Christopherson <seanjc@google.com>
To:     Paolo Bonzini <pbonzini@redhat.com>, Marc Zyngier <maz@kernel.org>,
        Oliver Upton <oliver.upton@linux.dev>,
        Huacai Chen <chenhuacai@kernel.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Anup Patel <anup@brainfault.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Sean Christopherson <seanjc@google.com>,
        "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Paul Moore <paul@paul-moore.com>,
        James Morris <jmorris@namei.org>,
        "Serge E. Hallyn" <serge@hallyn.com>
Cc:     kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        kvmarm@lists.linux.dev, linux-mips@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org,
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        linux-mm@kvack.org, linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Chao Peng <chao.p.peng@linux.intel.com>,
        Fuad Tabba <tabba@google.com>,
        Jarkko Sakkinen <jarkko@kernel.org>,
        Anish Moorthy <amoorthy@google.com>,
        Yu Zhang <yu.c.zhang@linux.intel.com>,
        Isaku Yamahata <isaku.yamahata@intel.com>,
        Xu Yilun <yilun.xu@intel.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Vishal Annapurve <vannapurve@google.com>,
        Ackerley Tng <ackerleytng@google.com>,
        Maciej Szmigiero <mail@maciej.szmigiero.name>,
        David Hildenbrand <david@redhat.com>,
        Quentin Perret <qperret@google.com>,
        Michael Roth <michael.roth@amd.com>,
        Wang <wei.w.wang@intel.com>,
        Liam Merwick <liam.merwick@oracle.com>,
        Isaku Yamahata <isaku.yamahata@gmail.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Rework and rename "struct kvm_hva_range" into "kvm_mmu_notifier_range" so
that the structure can be used to handle notifications that operate on gfn
context, i.e. that aren't tied to a host virtual address.

Practically speaking, this is a nop for 64-bit kernels as the only
meaningful change is to store start+end as u64s instead of unsigned longs.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 virt/kvm/kvm_main.c | 34 +++++++++++++++++++---------------
 1 file changed, 19 insertions(+), 15 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 486800a7024b..0524933856d4 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -541,18 +541,22 @@ static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn)
 	return container_of(mn, struct kvm, mmu_notifier);
 }
 
-typedef bool (*hva_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range);
+typedef bool (*gfn_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range);
 
 typedef void (*on_lock_fn_t)(struct kvm *kvm, unsigned long start,
 			     unsigned long end);
 
 typedef void (*on_unlock_fn_t)(struct kvm *kvm);
 
-struct kvm_hva_range {
-	unsigned long start;
-	unsigned long end;
+struct kvm_mmu_notifier_range {
+	/*
+	 * 64-bit addresses, as KVM notifiers can operate on host virtual
+	 * addresses (unsigned long) and guest physical addresses (64-bit).
+	 */
+	u64 start;
+	u64 end;
 	union kvm_mmu_notifier_arg arg;
-	hva_handler_t handler;
+	gfn_handler_t handler;
 	on_lock_fn_t on_lock;
 	on_unlock_fn_t on_unlock;
 	bool flush_on_ret;
@@ -581,7 +585,7 @@ static const union kvm_mmu_notifier_arg KVM_MMU_NOTIFIER_NO_ARG;
 	     node = interval_tree_iter_next(node, start, last))	     \
 
 static __always_inline int __kvm_handle_hva_range(struct kvm *kvm,
-						  const struct kvm_hva_range *range)
+						  const struct kvm_mmu_notifier_range *range)
 {
 	bool ret = false, locked = false;
 	struct kvm_gfn_range gfn_range;
@@ -608,9 +612,9 @@ static __always_inline int __kvm_handle_hva_range(struct kvm *kvm,
 			unsigned long hva_start, hva_end;
 
 			slot = container_of(node, struct kvm_memory_slot, hva_node[slots->node_idx]);
-			hva_start = max(range->start, slot->userspace_addr);
-			hva_end = min(range->end, slot->userspace_addr +
-						  (slot->npages << PAGE_SHIFT));
+			hva_start = max_t(unsigned long, range->start, slot->userspace_addr);
+			hva_end = min_t(unsigned long, range->end,
+					slot->userspace_addr + (slot->npages << PAGE_SHIFT));
 
 			/*
 			 * To optimize for the likely case where the address
@@ -660,10 +664,10 @@ static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn,
 						unsigned long start,
 						unsigned long end,
 						union kvm_mmu_notifier_arg arg,
-						hva_handler_t handler)
+						gfn_handler_t handler)
 {
 	struct kvm *kvm = mmu_notifier_to_kvm(mn);
-	const struct kvm_hva_range range = {
+	const struct kvm_mmu_notifier_range range = {
 		.start		= start,
 		.end		= end,
 		.arg		= arg,
@@ -680,10 +684,10 @@ static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn,
 static __always_inline int kvm_handle_hva_range_no_flush(struct mmu_notifier *mn,
 							 unsigned long start,
 							 unsigned long end,
-							 hva_handler_t handler)
+							 gfn_handler_t handler)
 {
 	struct kvm *kvm = mmu_notifier_to_kvm(mn);
-	const struct kvm_hva_range range = {
+	const struct kvm_mmu_notifier_range range = {
 		.start		= start,
 		.end		= end,
 		.handler	= handler,
@@ -771,7 +775,7 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
 					const struct mmu_notifier_range *range)
 {
 	struct kvm *kvm = mmu_notifier_to_kvm(mn);
-	const struct kvm_hva_range hva_range = {
+	const struct kvm_mmu_notifier_range hva_range = {
 		.start		= range->start,
 		.end		= range->end,
 		.handler	= kvm_unmap_gfn_range,
@@ -835,7 +839,7 @@ static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,
 					const struct mmu_notifier_range *range)
 {
 	struct kvm *kvm = mmu_notifier_to_kvm(mn);
-	const struct kvm_hva_range hva_range = {
+	const struct kvm_mmu_notifier_range hva_range = {
 		.start		= range->start,
 		.end		= range->end,
 		.handler	= (void *)kvm_null_fn,
-- 
2.42.0.283.g2d96d420d3-goog