From: kernel test robot <lkp@intel.com>
To: Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>
Cc: llvm@lists.linux.dev, kbuild-all@lists.01.org,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org
Subject: Re: [PATCH 3/5] KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits
Date: Tue, 1 Feb 2022 15:01:16 +0800 [thread overview]
Message-ID: <202202011400.EaZmWZ48-lkp@intel.com> (raw)
In-Reply-To: <20220201010838.1494405-4-seanjc@google.com>
Hi Sean,
I love your patch! Yet something to improve:
[auto build test ERROR on 26291c54e111ff6ba87a164d85d4a4e134b7315c]
url: https://github.com/0day-ci/linux/commits/Sean-Christopherson/x86-uaccess-CMPXCHG-KVM-bug-fixes/20220201-091001
base: 26291c54e111ff6ba87a164d85d4a4e134b7315c
config: i386-randconfig-a002 (https://download.01.org/0day-ci/archive/20220201/202202011400.EaZmWZ48-lkp@intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 6b1e844b69f15bb7dffaf9365cd2b355d2eb7579)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/c880d7a9df876f20dc3acdd893c5c71f3cda5029
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Sean-Christopherson/x86-uaccess-CMPXCHG-KVM-bug-fixes/20220201-091001
git checkout c880d7a9df876f20dc3acdd893c5c71f3cda5029
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
In file included from arch/x86/kvm/mmu/mmu.c:4246:
>> arch/x86/kvm/mmu/paging_tmpl.h:244:9: error: invalid output size for constraint '+a'
ret = __try_cmpxchg_user(ptep_user, &orig_pte, pte, fault);
^
arch/x86/include/asm/uaccess.h:629:11: note: expanded from macro '__try_cmpxchg_user'
__ret = !unsafe_try_cmpxchg_user(_ptr, _oldp, _nval, _label); \
^
arch/x86/include/asm/uaccess.h:606:18: note: expanded from macro 'unsafe_try_cmpxchg_user'
case 1: __ret = __try_cmpxchg_user_asm("b", "q", \
^
arch/x86/include/asm/uaccess.h:467:22: note: expanded from macro '__try_cmpxchg_user_asm'
[old] "+a" (__old) \
^
In file included from arch/x86/kvm/mmu/mmu.c:4246:
>> arch/x86/kvm/mmu/paging_tmpl.h:244:9: error: invalid output size for constraint '+a'
arch/x86/include/asm/uaccess.h:629:11: note: expanded from macro '__try_cmpxchg_user'
__ret = !unsafe_try_cmpxchg_user(_ptr, _oldp, _nval, _label); \
^
arch/x86/include/asm/uaccess.h:610:18: note: expanded from macro 'unsafe_try_cmpxchg_user'
case 2: __ret = __try_cmpxchg_user_asm("w", "r", \
^
arch/x86/include/asm/uaccess.h:467:22: note: expanded from macro '__try_cmpxchg_user_asm'
[old] "+a" (__old) \
^
In file included from arch/x86/kvm/mmu/mmu.c:4246:
>> arch/x86/kvm/mmu/paging_tmpl.h:244:9: error: invalid output size for constraint '+a'
arch/x86/include/asm/uaccess.h:629:11: note: expanded from macro '__try_cmpxchg_user'
__ret = !unsafe_try_cmpxchg_user(_ptr, _oldp, _nval, _label); \
^
arch/x86/include/asm/uaccess.h:614:18: note: expanded from macro 'unsafe_try_cmpxchg_user'
case 4: __ret = __try_cmpxchg_user_asm("l", "r", \
^
arch/x86/include/asm/uaccess.h:467:22: note: expanded from macro '__try_cmpxchg_user_asm'
[old] "+a" (__old) \
^
In file included from arch/x86/kvm/mmu/mmu.c:4250:
>> arch/x86/kvm/mmu/paging_tmpl.h:244:9: error: invalid output size for constraint '+a'
ret = __try_cmpxchg_user(ptep_user, &orig_pte, pte, fault);
^
arch/x86/include/asm/uaccess.h:629:11: note: expanded from macro '__try_cmpxchg_user'
__ret = !unsafe_try_cmpxchg_user(_ptr, _oldp, _nval, _label); \
^
arch/x86/include/asm/uaccess.h:606:18: note: expanded from macro 'unsafe_try_cmpxchg_user'
case 1: __ret = __try_cmpxchg_user_asm("b", "q", \
^
arch/x86/include/asm/uaccess.h:467:22: note: expanded from macro '__try_cmpxchg_user_asm'
[old] "+a" (__old) \
^
In file included from arch/x86/kvm/mmu/mmu.c:4250:
>> arch/x86/kvm/mmu/paging_tmpl.h:244:9: error: invalid output size for constraint '+a'
arch/x86/include/asm/uaccess.h:629:11: note: expanded from macro '__try_cmpxchg_user'
__ret = !unsafe_try_cmpxchg_user(_ptr, _oldp, _nval, _label); \
^
arch/x86/include/asm/uaccess.h:610:18: note: expanded from macro 'unsafe_try_cmpxchg_user'
case 2: __ret = __try_cmpxchg_user_asm("w", "r", \
^
arch/x86/include/asm/uaccess.h:467:22: note: expanded from macro '__try_cmpxchg_user_asm'
[old] "+a" (__old) \
^
In file included from arch/x86/kvm/mmu/mmu.c:4250:
>> arch/x86/kvm/mmu/paging_tmpl.h:244:9: error: invalid output size for constraint '+a'
arch/x86/include/asm/uaccess.h:629:11: note: expanded from macro '__try_cmpxchg_user'
__ret = !unsafe_try_cmpxchg_user(_ptr, _oldp, _nval, _label); \
^
arch/x86/include/asm/uaccess.h:614:18: note: expanded from macro 'unsafe_try_cmpxchg_user'
case 4: __ret = __try_cmpxchg_user_asm("l", "r", \
^
arch/x86/include/asm/uaccess.h:467:22: note: expanded from macro '__try_cmpxchg_user_asm'
[old] "+a" (__old) \
^
6 errors generated.
vim +244 arch/x86/kvm/mmu/paging_tmpl.h
191
192 static int FNAME(update_accessed_dirty_bits)(struct kvm_vcpu *vcpu,
193 struct kvm_mmu *mmu,
194 struct guest_walker *walker,
195 gpa_t addr, int write_fault)
196 {
197 unsigned level, index;
198 pt_element_t pte, orig_pte;
199 pt_element_t __user *ptep_user;
200 gfn_t table_gfn;
201 int ret;
202
203 /* dirty/accessed bits are not supported, so no need to update them */
204 if (!PT_HAVE_ACCESSED_DIRTY(mmu))
205 return 0;
206
207 for (level = walker->max_level; level >= walker->level; --level) {
208 pte = orig_pte = walker->ptes[level - 1];
209 table_gfn = walker->table_gfn[level - 1];
210 ptep_user = walker->ptep_user[level - 1];
211 index = offset_in_page(ptep_user) / sizeof(pt_element_t);
212 if (!(pte & PT_GUEST_ACCESSED_MASK)) {
213 trace_kvm_mmu_set_accessed_bit(table_gfn, index, sizeof(pte));
214 pte |= PT_GUEST_ACCESSED_MASK;
215 }
216 if (level == walker->level && write_fault &&
217 !(pte & PT_GUEST_DIRTY_MASK)) {
218 trace_kvm_mmu_set_dirty_bit(table_gfn, index, sizeof(pte));
219 #if PTTYPE == PTTYPE_EPT
220 if (kvm_x86_ops.nested_ops->write_log_dirty(vcpu, addr))
221 return -EINVAL;
222 #endif
223 pte |= PT_GUEST_DIRTY_MASK;
224 }
225 if (pte == orig_pte)
226 continue;
227
228 /*
229 * If the slot is read-only, simply do not process the accessed
230 * and dirty bits. This is the correct thing to do if the slot
231 * is ROM, and page tables in read-as-ROM/write-as-MMIO slots
232 * are only supported if the accessed and dirty bits are already
233 * set in the ROM (so that MMIO writes are never needed).
234 *
235 * Note that NPT does not allow this at all and faults, since
236 * it always wants nested page table entries for the guest
237 * page tables to be writable. And EPT works but will simply
238 * overwrite the read-only memory to set the accessed and dirty
239 * bits.
240 */
241 if (unlikely(!walker->pte_writable[level - 1]))
242 continue;
243
> 244 ret = __try_cmpxchg_user(ptep_user, &orig_pte, pte, fault);
245 if (ret)
246 return ret;
247
248 kvm_vcpu_mark_page_dirty(vcpu, table_gfn);
249 walker->ptes[level - 1] = pte;
250 }
251 return 0;
252 }
253
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
WARNING: multiple messages have this Message-ID (diff)
From: kernel test robot <lkp@intel.com>
To: kbuild-all@lists.01.org
Subject: Re: [PATCH 3/5] KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits
Date: Tue, 01 Feb 2022 15:01:16 +0800 [thread overview]
Message-ID: <202202011400.EaZmWZ48-lkp@intel.com> (raw)
In-Reply-To: <20220201010838.1494405-4-seanjc@google.com>
[-- Attachment #1: Type: text/plain, Size: 8813 bytes --]
Hi Sean,
I love your patch! Yet something to improve:
[auto build test ERROR on 26291c54e111ff6ba87a164d85d4a4e134b7315c]
url: https://github.com/0day-ci/linux/commits/Sean-Christopherson/x86-uaccess-CMPXCHG-KVM-bug-fixes/20220201-091001
base: 26291c54e111ff6ba87a164d85d4a4e134b7315c
config: i386-randconfig-a002 (https://download.01.org/0day-ci/archive/20220201/202202011400.EaZmWZ48-lkp(a)intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 6b1e844b69f15bb7dffaf9365cd2b355d2eb7579)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/c880d7a9df876f20dc3acdd893c5c71f3cda5029
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Sean-Christopherson/x86-uaccess-CMPXCHG-KVM-bug-fixes/20220201-091001
git checkout c880d7a9df876f20dc3acdd893c5c71f3cda5029
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
In file included from arch/x86/kvm/mmu/mmu.c:4246:
>> arch/x86/kvm/mmu/paging_tmpl.h:244:9: error: invalid output size for constraint '+a'
ret = __try_cmpxchg_user(ptep_user, &orig_pte, pte, fault);
^
arch/x86/include/asm/uaccess.h:629:11: note: expanded from macro '__try_cmpxchg_user'
__ret = !unsafe_try_cmpxchg_user(_ptr, _oldp, _nval, _label); \
^
arch/x86/include/asm/uaccess.h:606:18: note: expanded from macro 'unsafe_try_cmpxchg_user'
case 1: __ret = __try_cmpxchg_user_asm("b", "q", \
^
arch/x86/include/asm/uaccess.h:467:22: note: expanded from macro '__try_cmpxchg_user_asm'
[old] "+a" (__old) \
^
In file included from arch/x86/kvm/mmu/mmu.c:4246:
>> arch/x86/kvm/mmu/paging_tmpl.h:244:9: error: invalid output size for constraint '+a'
arch/x86/include/asm/uaccess.h:629:11: note: expanded from macro '__try_cmpxchg_user'
__ret = !unsafe_try_cmpxchg_user(_ptr, _oldp, _nval, _label); \
^
arch/x86/include/asm/uaccess.h:610:18: note: expanded from macro 'unsafe_try_cmpxchg_user'
case 2: __ret = __try_cmpxchg_user_asm("w", "r", \
^
arch/x86/include/asm/uaccess.h:467:22: note: expanded from macro '__try_cmpxchg_user_asm'
[old] "+a" (__old) \
^
In file included from arch/x86/kvm/mmu/mmu.c:4246:
>> arch/x86/kvm/mmu/paging_tmpl.h:244:9: error: invalid output size for constraint '+a'
arch/x86/include/asm/uaccess.h:629:11: note: expanded from macro '__try_cmpxchg_user'
__ret = !unsafe_try_cmpxchg_user(_ptr, _oldp, _nval, _label); \
^
arch/x86/include/asm/uaccess.h:614:18: note: expanded from macro 'unsafe_try_cmpxchg_user'
case 4: __ret = __try_cmpxchg_user_asm("l", "r", \
^
arch/x86/include/asm/uaccess.h:467:22: note: expanded from macro '__try_cmpxchg_user_asm'
[old] "+a" (__old) \
^
In file included from arch/x86/kvm/mmu/mmu.c:4250:
>> arch/x86/kvm/mmu/paging_tmpl.h:244:9: error: invalid output size for constraint '+a'
ret = __try_cmpxchg_user(ptep_user, &orig_pte, pte, fault);
^
arch/x86/include/asm/uaccess.h:629:11: note: expanded from macro '__try_cmpxchg_user'
__ret = !unsafe_try_cmpxchg_user(_ptr, _oldp, _nval, _label); \
^
arch/x86/include/asm/uaccess.h:606:18: note: expanded from macro 'unsafe_try_cmpxchg_user'
case 1: __ret = __try_cmpxchg_user_asm("b", "q", \
^
arch/x86/include/asm/uaccess.h:467:22: note: expanded from macro '__try_cmpxchg_user_asm'
[old] "+a" (__old) \
^
In file included from arch/x86/kvm/mmu/mmu.c:4250:
>> arch/x86/kvm/mmu/paging_tmpl.h:244:9: error: invalid output size for constraint '+a'
arch/x86/include/asm/uaccess.h:629:11: note: expanded from macro '__try_cmpxchg_user'
__ret = !unsafe_try_cmpxchg_user(_ptr, _oldp, _nval, _label); \
^
arch/x86/include/asm/uaccess.h:610:18: note: expanded from macro 'unsafe_try_cmpxchg_user'
case 2: __ret = __try_cmpxchg_user_asm("w", "r", \
^
arch/x86/include/asm/uaccess.h:467:22: note: expanded from macro '__try_cmpxchg_user_asm'
[old] "+a" (__old) \
^
In file included from arch/x86/kvm/mmu/mmu.c:4250:
>> arch/x86/kvm/mmu/paging_tmpl.h:244:9: error: invalid output size for constraint '+a'
arch/x86/include/asm/uaccess.h:629:11: note: expanded from macro '__try_cmpxchg_user'
__ret = !unsafe_try_cmpxchg_user(_ptr, _oldp, _nval, _label); \
^
arch/x86/include/asm/uaccess.h:614:18: note: expanded from macro 'unsafe_try_cmpxchg_user'
case 4: __ret = __try_cmpxchg_user_asm("l", "r", \
^
arch/x86/include/asm/uaccess.h:467:22: note: expanded from macro '__try_cmpxchg_user_asm'
[old] "+a" (__old) \
^
6 errors generated.
vim +244 arch/x86/kvm/mmu/paging_tmpl.h
191
192 static int FNAME(update_accessed_dirty_bits)(struct kvm_vcpu *vcpu,
193 struct kvm_mmu *mmu,
194 struct guest_walker *walker,
195 gpa_t addr, int write_fault)
196 {
197 unsigned level, index;
198 pt_element_t pte, orig_pte;
199 pt_element_t __user *ptep_user;
200 gfn_t table_gfn;
201 int ret;
202
203 /* dirty/accessed bits are not supported, so no need to update them */
204 if (!PT_HAVE_ACCESSED_DIRTY(mmu))
205 return 0;
206
207 for (level = walker->max_level; level >= walker->level; --level) {
208 pte = orig_pte = walker->ptes[level - 1];
209 table_gfn = walker->table_gfn[level - 1];
210 ptep_user = walker->ptep_user[level - 1];
211 index = offset_in_page(ptep_user) / sizeof(pt_element_t);
212 if (!(pte & PT_GUEST_ACCESSED_MASK)) {
213 trace_kvm_mmu_set_accessed_bit(table_gfn, index, sizeof(pte));
214 pte |= PT_GUEST_ACCESSED_MASK;
215 }
216 if (level == walker->level && write_fault &&
217 !(pte & PT_GUEST_DIRTY_MASK)) {
218 trace_kvm_mmu_set_dirty_bit(table_gfn, index, sizeof(pte));
219 #if PTTYPE == PTTYPE_EPT
220 if (kvm_x86_ops.nested_ops->write_log_dirty(vcpu, addr))
221 return -EINVAL;
222 #endif
223 pte |= PT_GUEST_DIRTY_MASK;
224 }
225 if (pte == orig_pte)
226 continue;
227
228 /*
229 * If the slot is read-only, simply do not process the accessed
230 * and dirty bits. This is the correct thing to do if the slot
231 * is ROM, and page tables in read-as-ROM/write-as-MMIO slots
232 * are only supported if the accessed and dirty bits are already
233 * set in the ROM (so that MMIO writes are never needed).
234 *
235 * Note that NPT does not allow this at all and faults, since
236 * it always wants nested page table entries for the guest
237 * page tables to be writable. And EPT works but will simply
238 * overwrite the read-only memory to set the accessed and dirty
239 * bits.
240 */
241 if (unlikely(!walker->pte_writable[level - 1]))
242 continue;
243
> 244 ret = __try_cmpxchg_user(ptep_user, &orig_pte, pte, fault);
245 if (ret)
246 return ret;
247
248 kvm_vcpu_mark_page_dirty(vcpu, table_gfn);
249 walker->ptes[level - 1] = pte;
250 }
251 return 0;
252 }
253
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org
next prev parent reply other threads:[~2022-02-01 7:01 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-01 1:08 [PATCH 0/5] x86: uaccess CMPXCHG + KVM bug fixes Sean Christopherson
2022-02-01 1:08 ` [PATCH 1/5] Kconfig: Add option for asm goto w/ tied outputs to workaround clang-13 bug Sean Christopherson
2022-02-01 20:16 ` Nick Desaulniers
2022-02-01 20:56 ` Sean Christopherson
2022-02-01 21:15 ` Nick Desaulniers
2022-02-01 1:08 ` [PATCH 2/5] x86/uaccess: Implement macros for CMPXCHG on user addresses Sean Christopherson
2022-02-01 1:08 ` [PATCH 3/5] KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits Sean Christopherson
2022-02-01 7:01 ` kernel test robot [this message]
2022-02-01 7:01 ` kernel test robot
2022-02-01 19:44 ` Sean Christopherson
2022-02-01 19:44 ` Sean Christopherson
2022-02-01 19:53 ` Nick Desaulniers
2022-02-01 19:53 ` Nick Desaulniers
2022-02-01 13:25 ` kernel test robot
2022-02-01 13:25 ` kernel test robot
2022-02-01 1:08 ` [PATCH 4/5] KVM: x86: Use __try_cmpxchg_user() to emulate atomic accesses Sean Christopherson
2022-02-01 9:25 ` kernel test robot
2022-02-01 9:25 ` kernel test robot
2022-02-01 1:08 ` [PATCH 5/5] KVM: x86: Bail to userspace if emulation of atomic user access faults Sean Christopherson
2022-02-01 17:09 ` [PATCH 0/5] x86: uaccess CMPXCHG + KVM bug fixes Tadeusz Struk
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