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Message-ID: <202510211010.XRaEeuBa-lkp@intel.com>
Date: Tue, 21 Oct 2025 10:38:33 +0800
From: kernel test robot <lkp@...el.com>
To: fangyu.yu@...ux.alibaba.com, anup@...infault.org, atish.patra@...ux.dev,
pjw@...nel.org, palmer@...belt.com, aou@...s.berkeley.edu,
alex@...ti.fr, pbonzini@...hat.com, jiangyifei@...wei.com
Cc: llvm@...ts.linux.dev, oe-kbuild-all@...ts.linux.dev, guoren@...nel.org,
kvm@...r.kernel.org, kvm-riscv@...ts.infradead.org,
linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
Fangyu Yu <fangyu.yu@...ux.alibaba.com>
Subject: Re: [PATCH] RISC-V: KVM: Remove automatic I/O mapping for VM_PFNMAP
Hi,
kernel test robot noticed the following build warnings:
[auto build test WARNING on kvm/queue]
[also build test WARNING on kvm/next linus/master v6.18-rc2 next-20251020]
[cannot apply to kvm/linux-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/fangyu-yu-linux-alibaba-com/RISC-V-KVM-Remove-automatic-I-O-mapping-for-VM_PFNMAP/20251020-210957
base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git queue
patch link: https://lore.kernel.org/r/20251020130801.68356-1-fangyu.yu%40linux.alibaba.com
patch subject: [PATCH] RISC-V: KVM: Remove automatic I/O mapping for VM_PFNMAP
config: riscv-defconfig (https://download.01.org/0day-ci/archive/20251021/202510211010.XRaEeuBa-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project 754ebc6ebb9fb9fbee7aef33478c74ea74949853)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251021/202510211010.XRaEeuBa-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202510211010.XRaEeuBa-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> arch/riscv/kvm/mmu.c:211:9: warning: variable 'vm_start' set but not used [-Wunused-but-set-variable]
211 | hva_t vm_start, vm_end;
| ^
>> arch/riscv/kvm/mmu.c:174:8: warning: variable 'base_gpa' set but not used [-Wunused-but-set-variable]
174 | gpa_t base_gpa;
| ^
2 warnings generated.
vim +/vm_start +211 arch/riscv/kvm/mmu.c
99cdc6c18c2d815 Anup Patel 2021-09-27 167
99cdc6c18c2d815 Anup Patel 2021-09-27 168 int kvm_arch_prepare_memory_region(struct kvm *kvm,
537a17b31493009 Sean Christopherson 2021-12-06 169 const struct kvm_memory_slot *old,
537a17b31493009 Sean Christopherson 2021-12-06 170 struct kvm_memory_slot *new,
99cdc6c18c2d815 Anup Patel 2021-09-27 171 enum kvm_mr_change change)
99cdc6c18c2d815 Anup Patel 2021-09-27 172 {
d01495d4cffb327 Sean Christopherson 2021-12-06 173 hva_t hva, reg_end, size;
d01495d4cffb327 Sean Christopherson 2021-12-06 @174 gpa_t base_gpa;
d01495d4cffb327 Sean Christopherson 2021-12-06 175 bool writable;
9d05c1fee837572 Anup Patel 2021-09-27 176 int ret = 0;
9d05c1fee837572 Anup Patel 2021-09-27 177
9d05c1fee837572 Anup Patel 2021-09-27 178 if (change != KVM_MR_CREATE && change != KVM_MR_MOVE &&
9d05c1fee837572 Anup Patel 2021-09-27 179 change != KVM_MR_FLAGS_ONLY)
99cdc6c18c2d815 Anup Patel 2021-09-27 180 return 0;
9d05c1fee837572 Anup Patel 2021-09-27 181
9d05c1fee837572 Anup Patel 2021-09-27 182 /*
9d05c1fee837572 Anup Patel 2021-09-27 183 * Prevent userspace from creating a memory region outside of the GPA
9d05c1fee837572 Anup Patel 2021-09-27 184 * space addressable by the KVM guest GPA space.
9d05c1fee837572 Anup Patel 2021-09-27 185 */
537a17b31493009 Sean Christopherson 2021-12-06 186 if ((new->base_gfn + new->npages) >=
dd82e35638d67f4 Anup Patel 2025-06-18 187 (kvm_riscv_gstage_gpa_size >> PAGE_SHIFT))
9d05c1fee837572 Anup Patel 2021-09-27 188 return -EFAULT;
9d05c1fee837572 Anup Patel 2021-09-27 189
d01495d4cffb327 Sean Christopherson 2021-12-06 190 hva = new->userspace_addr;
d01495d4cffb327 Sean Christopherson 2021-12-06 191 size = new->npages << PAGE_SHIFT;
d01495d4cffb327 Sean Christopherson 2021-12-06 192 reg_end = hva + size;
d01495d4cffb327 Sean Christopherson 2021-12-06 193 base_gpa = new->base_gfn << PAGE_SHIFT;
d01495d4cffb327 Sean Christopherson 2021-12-06 194 writable = !(new->flags & KVM_MEM_READONLY);
d01495d4cffb327 Sean Christopherson 2021-12-06 195
9d05c1fee837572 Anup Patel 2021-09-27 196 mmap_read_lock(current->mm);
9d05c1fee837572 Anup Patel 2021-09-27 197
9d05c1fee837572 Anup Patel 2021-09-27 198 /*
9d05c1fee837572 Anup Patel 2021-09-27 199 * A memory region could potentially cover multiple VMAs, and
b35152e0fb35983 Fangyu Yu 2025-10-20 200 * any holes between them, so iterate over all of them.
9d05c1fee837572 Anup Patel 2021-09-27 201 *
9d05c1fee837572 Anup Patel 2021-09-27 202 * +--------------------------------------------+
9d05c1fee837572 Anup Patel 2021-09-27 203 * +---------------+----------------+ +----------------+
9d05c1fee837572 Anup Patel 2021-09-27 204 * | : VMA 1 | VMA 2 | | VMA 3 : |
9d05c1fee837572 Anup Patel 2021-09-27 205 * +---------------+----------------+ +----------------+
9d05c1fee837572 Anup Patel 2021-09-27 206 * | memory region |
9d05c1fee837572 Anup Patel 2021-09-27 207 * +--------------------------------------------+
9d05c1fee837572 Anup Patel 2021-09-27 208 */
9d05c1fee837572 Anup Patel 2021-09-27 209 do {
fce11b667022766 Quan Zhou 2025-06-17 210 struct vm_area_struct *vma;
9d05c1fee837572 Anup Patel 2021-09-27 @211 hva_t vm_start, vm_end;
9d05c1fee837572 Anup Patel 2021-09-27 212
fce11b667022766 Quan Zhou 2025-06-17 213 vma = find_vma_intersection(current->mm, hva, reg_end);
fce11b667022766 Quan Zhou 2025-06-17 214 if (!vma)
9d05c1fee837572 Anup Patel 2021-09-27 215 break;
9d05c1fee837572 Anup Patel 2021-09-27 216
9d05c1fee837572 Anup Patel 2021-09-27 217 /*
9d05c1fee837572 Anup Patel 2021-09-27 218 * Mapping a read-only VMA is only allowed if the
9d05c1fee837572 Anup Patel 2021-09-27 219 * memory region is configured as read-only.
9d05c1fee837572 Anup Patel 2021-09-27 220 */
9d05c1fee837572 Anup Patel 2021-09-27 221 if (writable && !(vma->vm_flags & VM_WRITE)) {
9d05c1fee837572 Anup Patel 2021-09-27 222 ret = -EPERM;
9d05c1fee837572 Anup Patel 2021-09-27 223 break;
9d05c1fee837572 Anup Patel 2021-09-27 224 }
9d05c1fee837572 Anup Patel 2021-09-27 225
9d05c1fee837572 Anup Patel 2021-09-27 226 /* Take the intersection of this VMA with the memory region */
9d05c1fee837572 Anup Patel 2021-09-27 227 vm_start = max(hva, vma->vm_start);
9d05c1fee837572 Anup Patel 2021-09-27 228 vm_end = min(reg_end, vma->vm_end);
9d05c1fee837572 Anup Patel 2021-09-27 229
9d05c1fee837572 Anup Patel 2021-09-27 230 if (vma->vm_flags & VM_PFNMAP) {
9d05c1fee837572 Anup Patel 2021-09-27 231 /* IO region dirty page logging not allowed */
537a17b31493009 Sean Christopherson 2021-12-06 232 if (new->flags & KVM_MEM_LOG_DIRTY_PAGES) {
9d05c1fee837572 Anup Patel 2021-09-27 233 ret = -EINVAL;
9d05c1fee837572 Anup Patel 2021-09-27 234 goto out;
9d05c1fee837572 Anup Patel 2021-09-27 235 }
9d05c1fee837572 Anup Patel 2021-09-27 236 }
9d05c1fee837572 Anup Patel 2021-09-27 237 hva = vm_end;
9d05c1fee837572 Anup Patel 2021-09-27 238 } while (hva < reg_end);
9d05c1fee837572 Anup Patel 2021-09-27 239
9d05c1fee837572 Anup Patel 2021-09-27 240 out:
9d05c1fee837572 Anup Patel 2021-09-27 241 mmap_read_unlock(current->mm);
9d05c1fee837572 Anup Patel 2021-09-27 242 return ret;
99cdc6c18c2d815 Anup Patel 2021-09-27 243 }
99cdc6c18c2d815 Anup Patel 2021-09-27 244
--
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