From 3a2ef25070d8135a62dfca5bff35114f520c52ad Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 18 Jul 2025 18:11:27 +0200 Subject: [PATCH 111/115] memory: Export a helper to get intersection of a MemoryRegionSection with a given range RH-Author: Paolo Bonzini RH-MergeRequest: 391: TDX support, including attestation and device assignment RH-Jira: RHEL-15710 RHEL-20798 RHEL-49728 RH-Acked-by: Yash Mankad RH-Acked-by: Peter Xu RH-Acked-by: David Hildenbrand RH-Commit: [111/115] d7812c678358993209bbe280985f58fce9a34e18 (bonzini/rhel-qemu-kvm) Rename the helper to memory_region_section_intersect_range() to make it more generic. Meanwhile, define the @end as Int128 and replace the related operations with Int128_* format since the helper is exported as a wider API. Suggested-by: Alexey Kardashevskiy Reviewed-by: Alexey Kardashevskiy Reviewed-by: Pankaj Gupta Reviewed-by: David Hildenbrand Reviewed-by: Zhao Liu Reviewed-by: Xiaoyao Li Signed-off-by: Chenyi Qiang Link: https://lore.kernel.org/r/20250612082747.51539-2-chenyi.qiang@intel.com Signed-off-by: Peter Xu (cherry picked from commit f47a672a72acd6e2712031f0bc4d4f3ae4b6302c) Signed-off-by: Paolo Bonzini --- hw/virtio/virtio-mem.c | 32 +++++--------------------------- include/exec/memory.h | 30 ++++++++++++++++++++++++++++++ 2 files changed, 35 insertions(+), 27 deletions(-) diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c index 4977658312..ae26133f58 100644 --- a/hw/virtio/virtio-mem.c +++ b/hw/virtio/virtio-mem.c @@ -244,28 +244,6 @@ static int virtio_mem_for_each_plugged_range(VirtIOMEM *vmem, void *arg, return ret; } -/* - * Adjust the memory section to cover the intersection with the given range. - * - * Returns false if the intersection is empty, otherwise returns true. - */ -static bool virtio_mem_intersect_memory_section(MemoryRegionSection *s, - uint64_t offset, uint64_t size) -{ - uint64_t start = MAX(s->offset_within_region, offset); - uint64_t end = MIN(s->offset_within_region + int128_get64(s->size), - offset + size); - - if (end <= start) { - return false; - } - - s->offset_within_address_space += start - s->offset_within_region; - s->offset_within_region = start; - s->size = int128_make64(end - start); - return true; -} - typedef int (*virtio_mem_section_cb)(MemoryRegionSection *s, void *arg); static int virtio_mem_for_each_plugged_section(const VirtIOMEM *vmem, @@ -287,7 +265,7 @@ static int virtio_mem_for_each_plugged_section(const VirtIOMEM *vmem, first_bit + 1) - 1; size = (last_bit - first_bit + 1) * vmem->block_size; - if (!virtio_mem_intersect_memory_section(&tmp, offset, size)) { + if (!memory_region_section_intersect_range(&tmp, offset, size)) { break; } ret = cb(&tmp, arg); @@ -319,7 +297,7 @@ static int virtio_mem_for_each_unplugged_section(const VirtIOMEM *vmem, first_bit + 1) - 1; size = (last_bit - first_bit + 1) * vmem->block_size; - if (!virtio_mem_intersect_memory_section(&tmp, offset, size)) { + if (!memory_region_section_intersect_range(&tmp, offset, size)) { break; } ret = cb(&tmp, arg); @@ -355,7 +333,7 @@ static void virtio_mem_notify_unplug(VirtIOMEM *vmem, uint64_t offset, QLIST_FOREACH(rdl, &vmem->rdl_list, next) { MemoryRegionSection tmp = *rdl->section; - if (!virtio_mem_intersect_memory_section(&tmp, offset, size)) { + if (!memory_region_section_intersect_range(&tmp, offset, size)) { continue; } rdl->notify_discard(rdl, &tmp); @@ -371,7 +349,7 @@ static int virtio_mem_notify_plug(VirtIOMEM *vmem, uint64_t offset, QLIST_FOREACH(rdl, &vmem->rdl_list, next) { MemoryRegionSection tmp = *rdl->section; - if (!virtio_mem_intersect_memory_section(&tmp, offset, size)) { + if (!memory_region_section_intersect_range(&tmp, offset, size)) { continue; } ret = rdl->notify_populate(rdl, &tmp); @@ -388,7 +366,7 @@ static int virtio_mem_notify_plug(VirtIOMEM *vmem, uint64_t offset, if (rdl2 == rdl) { break; } - if (!virtio_mem_intersect_memory_section(&tmp, offset, size)) { + if (!memory_region_section_intersect_range(&tmp, offset, size)) { continue; } rdl2->notify_discard(rdl2, &tmp); diff --git a/include/exec/memory.h b/include/exec/memory.h index 296fd068c0..71b4a411cc 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -1200,6 +1200,36 @@ MemoryRegionSection *memory_region_section_new_copy(MemoryRegionSection *s); */ void memory_region_section_free_copy(MemoryRegionSection *s); +/** + * memory_region_section_intersect_range: Adjust the memory section to cover + * the intersection with the given range. + * + * @s: the #MemoryRegionSection to be adjusted + * @offset: the offset of the given range in the memory region + * @size: the size of the given range + * + * Returns false if the intersection is empty, otherwise returns true. + */ +static inline bool memory_region_section_intersect_range(MemoryRegionSection *s, + uint64_t offset, + uint64_t size) +{ + uint64_t start = MAX(s->offset_within_region, offset); + Int128 end = int128_min(int128_add(int128_make64(s->offset_within_region), + s->size), + int128_add(int128_make64(offset), + int128_make64(size))); + + if (int128_le(end, int128_make64(start))) { + return false; + } + + s->offset_within_address_space += start - s->offset_within_region; + s->offset_within_region = start; + s->size = int128_sub(end, int128_make64(start)); + return true; +} + /** * memory_region_init: Initialize a memory region * -- 2.50.1