| Message ID | 20200117125834.14552-3-sergey.dyasli@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | basic KASAN support for Xen PV domains | expand |
On 1/17/20 7:58 AM, Sergey Dyasli wrote: > --- a/arch/x86/mm/kasan_init_64.c > +++ b/arch/x86/mm/kasan_init_64.c > @@ -13,6 +13,9 @@ > #include <linux/sched/task.h> > #include <linux/vmalloc.h> > > +#include <xen/xen.h> > +#include <xen/xen-ops.h> > + > #include <asm/e820/types.h> > #include <asm/pgalloc.h> > #include <asm/tlbflush.h> > @@ -332,6 +335,11 @@ void __init kasan_early_init(void) > for (i = 0; pgtable_l5_enabled() && i < PTRS_PER_P4D; i++) > kasan_early_shadow_p4d[i] = __p4d(p4d_val); > > + if (xen_pv_domain()) { > + pgd_t *pv_top_pgt = xen_pv_kasan_early_init(); > + kasan_map_early_shadow(pv_top_pgt); > + } > + I'd suggest replacing this with xen_kasan_early_init() and doing everything, including PV check, there. This way non-Xen code won't need to be aware of Xen-specific details such as guest types. > kasan_map_early_shadow(early_top_pgt); > kasan_map_early_shadow(init_top_pgt); > } > @@ -369,6 +377,8 @@ void __init kasan_init(void) > __pgd(__pa(tmp_p4d_table) | _KERNPG_TABLE)); > } > > + xen_pv_kasan_pin_pgd(early_top_pgt); > + And drop "_pv" here (and below) for the same reason. -boris > load_cr3(early_top_pgt); > __flush_tlb_all(); > > @@ -433,6 +443,8 @@ void __init kasan_init(void) > load_cr3(init_top_pgt); > __flush_tlb_all(); > > + xen_pv_kasan_unpin_pgd(early_top_pgt); > + >
Hi Sergey,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on xen-tip/linux-next]
[also build test ERROR on tip/x86/mm tip/auto-latest linux/master linus/master v5.5-rc7 next-20200117]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
url: https://github.com/0day-ci/linux/commits/Sergey-Dyasli/basic-KASAN-support-for-Xen-PV-domains/20200118-073544
base: https://git.kernel.org/pub/scm/linux/kernel/git/xen/tip.git linux-next
config: i386-randconfig-f003-20200120 (attached as .config)
compiler: gcc-7 (Debian 7.5.0-3) 7.5.0
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
arch/x86//xen/mmu_pv.c: In function 'xen_pv_kasan_early_init':
>> arch/x86//xen/mmu_pv.c:1778:16: error: 'kasan_early_shadow_pud' undeclared (first use in this function); did you mean 'kasan_free_shadow'?
set_page_prot(kasan_early_shadow_pud, PAGE_KERNEL_RO);
^~~~~~~~~~~~~~~~~~~~~~
kasan_free_shadow
arch/x86//xen/mmu_pv.c:1778:16: note: each undeclared identifier is reported only once for each function it appears in
>> arch/x86//xen/mmu_pv.c:1779:16: error: 'kasan_early_shadow_pmd' undeclared (first use in this function); did you mean 'kasan_early_shadow_pud'?
set_page_prot(kasan_early_shadow_pmd, PAGE_KERNEL_RO);
^~~~~~~~~~~~~~~~~~~~~~
kasan_early_shadow_pud
>> arch/x86//xen/mmu_pv.c:1780:16: error: 'kasan_early_shadow_pte' undeclared (first use in this function); did you mean 'kasan_early_shadow_pmd'?
set_page_prot(kasan_early_shadow_pte, PAGE_KERNEL_RO);
^~~~~~~~~~~~~~~~~~~~~~
kasan_early_shadow_pmd
vim +1778 arch/x86//xen/mmu_pv.c
1774
1775 pgd_t * __init xen_pv_kasan_early_init(void)
1776 {
1777 /* PV page tables must be read-only */
> 1778 set_page_prot(kasan_early_shadow_pud, PAGE_KERNEL_RO);
> 1779 set_page_prot(kasan_early_shadow_pmd, PAGE_KERNEL_RO);
> 1780 set_page_prot(kasan_early_shadow_pte, PAGE_KERNEL_RO);
1781
1782 /* Return a pointer to the initial PV page tables */
1783 return (pgd_t *)xen_start_info->pt_base;
1784 }
1785
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org Intel Corporation
Hi Sergey,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on xen-tip/linux-next]
[also build test ERROR on tip/x86/mm tip/auto-latest linux/master linus/master v5.5-rc7 next-20200121]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
url: https://github.com/0day-ci/linux/commits/Sergey-Dyasli/basic-KASAN-support-for-Xen-PV-domains/20200118-073544
base: https://git.kernel.org/pub/scm/linux/kernel/git/xen/tip.git linux-next
config: x86_64-randconfig-a002-20200121 (attached as .config)
compiler: gcc-6 (Debian 6.3.0-18+deb9u1) 6.3.0 20170516
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64
If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
arch/x86/xen/mmu_pv.c: In function 'xen_pv_kasan_early_init':
>> arch/x86/xen/mmu_pv.c:1778:16: error: 'kasan_early_shadow_pud' undeclared (first use in this function)
set_page_prot(kasan_early_shadow_pud, PAGE_KERNEL_RO);
^~~~~~~~~~~~~~~~~~~~~~
arch/x86/xen/mmu_pv.c:1778:16: note: each undeclared identifier is reported only once for each function it appears in
>> arch/x86/xen/mmu_pv.c:1779:16: error: 'kasan_early_shadow_pmd' undeclared (first use in this function)
set_page_prot(kasan_early_shadow_pmd, PAGE_KERNEL_RO);
^~~~~~~~~~~~~~~~~~~~~~
>> arch/x86/xen/mmu_pv.c:1780:16: error: 'kasan_early_shadow_pte' undeclared (first use in this function)
set_page_prot(kasan_early_shadow_pte, PAGE_KERNEL_RO);
^~~~~~~~~~~~~~~~~~~~~~
vim +/kasan_early_shadow_pud +1778 arch/x86/xen/mmu_pv.c
1774
1775 pgd_t * __init xen_pv_kasan_early_init(void)
1776 {
1777 /* PV page tables must be read-only */
> 1778 set_page_prot(kasan_early_shadow_pud, PAGE_KERNEL_RO);
> 1779 set_page_prot(kasan_early_shadow_pmd, PAGE_KERNEL_RO);
> 1780 set_page_prot(kasan_early_shadow_pte, PAGE_KERNEL_RO);
1781
1782 /* Return a pointer to the initial PV page tables */
1783 return (pgd_t *)xen_start_info->pt_base;
1784 }
1785
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org Intel Corporation
On 17/01/2020 14:56, Boris Ostrovsky wrote: > > > On 1/17/20 7:58 AM, Sergey Dyasli wrote: >> --- a/arch/x86/mm/kasan_init_64.c >> +++ b/arch/x86/mm/kasan_init_64.c >> @@ -13,6 +13,9 @@ >> #include <linux/sched/task.h> >> #include <linux/vmalloc.h> >> +#include <xen/xen.h> >> +#include <xen/xen-ops.h> >> + >> #include <asm/e820/types.h> >> #include <asm/pgalloc.h> >> #include <asm/tlbflush.h> >> @@ -332,6 +335,11 @@ void __init kasan_early_init(void) >> for (i = 0; pgtable_l5_enabled() && i < PTRS_PER_P4D; i++) >> kasan_early_shadow_p4d[i] = __p4d(p4d_val); >> + if (xen_pv_domain()) { >> + pgd_t *pv_top_pgt = xen_pv_kasan_early_init(); >> + kasan_map_early_shadow(pv_top_pgt); >> + } >> + > > > I'd suggest replacing this with xen_kasan_early_init() and doing everything, including PV check, there. This way non-Xen code won't need to be aware of Xen-specific details such as guest types. This would require exporting kasan_map_early_shadow() via kasan.h. I'm fine with either approach. >> kasan_map_early_shadow(early_top_pgt); >> kasan_map_early_shadow(init_top_pgt); >> } >> @@ -369,6 +377,8 @@ void __init kasan_init(void) >> __pgd(__pa(tmp_p4d_table) | _KERNPG_TABLE)); >> } >> + xen_pv_kasan_pin_pgd(early_top_pgt); >> + > > And drop "_pv" here (and below) for the same reason. This is a reasonable suggestion. >> load_cr3(early_top_pgt); >> __flush_tlb_all(); >> @@ -433,6 +443,8 @@ void __init kasan_init(void) >> load_cr3(init_top_pgt); >> __flush_tlb_all(); >> + xen_pv_kasan_unpin_pgd(early_top_pgt); >> + >> -- Thanks, Sergey
diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c index cf5bc37c90ac..902a6a152d33 100644 --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -13,6 +13,9 @@ #include <linux/sched/task.h> #include <linux/vmalloc.h> +#include <xen/xen.h> +#include <xen/xen-ops.h> + #include <asm/e820/types.h> #include <asm/pgalloc.h> #include <asm/tlbflush.h> @@ -332,6 +335,11 @@ void __init kasan_early_init(void) for (i = 0; pgtable_l5_enabled() && i < PTRS_PER_P4D; i++) kasan_early_shadow_p4d[i] = __p4d(p4d_val); + if (xen_pv_domain()) { + pgd_t *pv_top_pgt = xen_pv_kasan_early_init(); + kasan_map_early_shadow(pv_top_pgt); + } + kasan_map_early_shadow(early_top_pgt); kasan_map_early_shadow(init_top_pgt); } @@ -369,6 +377,8 @@ void __init kasan_init(void) __pgd(__pa(tmp_p4d_table) | _KERNPG_TABLE)); } + xen_pv_kasan_pin_pgd(early_top_pgt); + load_cr3(early_top_pgt); __flush_tlb_all(); @@ -433,6 +443,8 @@ void __init kasan_init(void) load_cr3(init_top_pgt); __flush_tlb_all(); + xen_pv_kasan_unpin_pgd(early_top_pgt); + /* * kasan_early_shadow_page has been used as early shadow memory, thus * it may contain some garbage. Now we can clear and write protect it, diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile index 084de77a109e..102fad0b0bca 100644 --- a/arch/x86/xen/Makefile +++ b/arch/x86/xen/Makefile @@ -1,3 +1,10 @@ +KASAN_SANITIZE_enlighten_pv.o := n +KASAN_SANITIZE_enlighten.o := n +KASAN_SANITIZE_irq.o := n +KASAN_SANITIZE_mmu_pv.o := n +KASAN_SANITIZE_p2m.o := n +KASAN_SANITIZE_multicalls.o := n + # SPDX-License-Identifier: GPL-2.0 OBJECT_FILES_NON_STANDARD_xen-asm_$(BITS).o := y diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c index ae4a41ca19f6..27de55699f24 100644 --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -72,6 +72,7 @@ #include <asm/mwait.h> #include <asm/pci_x86.h> #include <asm/cpu.h> +#include <asm/kasan.h> #ifdef CONFIG_ACPI #include <linux/acpi.h> @@ -1231,6 +1232,8 @@ asmlinkage __visible void __init xen_start_kernel(void) /* Get mfn list */ xen_build_dynamic_phys_to_machine(); + kasan_early_init(); + /* * Set up kernel GDT and segment registers, mainly so that * -fstack-protector code can be executed. diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c index c8dbee62ec2a..5cd63e37a2db 100644 --- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -1771,6 +1771,36 @@ static void __init set_page_prot(void *addr, pgprot_t prot) { return set_page_prot_flags(addr, prot, UVMF_NONE); } + +pgd_t * __init xen_pv_kasan_early_init(void) +{ + /* PV page tables must be read-only */ + set_page_prot(kasan_early_shadow_pud, PAGE_KERNEL_RO); + set_page_prot(kasan_early_shadow_pmd, PAGE_KERNEL_RO); + set_page_prot(kasan_early_shadow_pte, PAGE_KERNEL_RO); + + /* Return a pointer to the initial PV page tables */ + return (pgd_t *)xen_start_info->pt_base; +} + +void __init xen_pv_kasan_pin_pgd(pgd_t *pgd) +{ + if (!xen_pv_domain()) + return; + + set_page_prot(pgd, PAGE_KERNEL_RO); + pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa_symbol(pgd))); +} + +void __init xen_pv_kasan_unpin_pgd(pgd_t *pgd) +{ + if (!xen_pv_domain()) + return; + + pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa_symbol(pgd))); + set_page_prot(pgd, PAGE_KERNEL); +} + #ifdef CONFIG_X86_32 static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn) { @@ -1943,6 +1973,14 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) if (i && i < pgd_index(__START_KERNEL_map)) init_top_pgt[i] = ((pgd_t *)xen_start_info->pt_base)[i]; +#ifdef CONFIG_KASAN + /* Copy KASAN mappings */ + for (i = pgd_index(KASAN_SHADOW_START); + i < pgd_index(KASAN_SHADOW_END); + i++) + init_top_pgt[i] = ((pgd_t *)xen_start_info->pt_base)[i]; +#endif /* ifdef CONFIG_KASAN */ + /* Make pagetable pieces RO */ set_page_prot(init_top_pgt, PAGE_KERNEL_RO); set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO); diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile index 0c4efa6fe450..1e9e1e41c0a8 100644 --- a/drivers/xen/Makefile +++ b/drivers/xen/Makefile @@ -1,4 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 +KASAN_SANITIZE_features.o := n + obj-$(CONFIG_HOTPLUG_CPU) += cpu_hotplug.o obj-y += grant-table.o features.o balloon.o manage.o preempt.o time.o obj-y += mem-reservation.o diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h index d89969aa9942..3d20f000af12 100644 --- a/include/xen/xen-ops.h +++ b/include/xen/xen-ops.h @@ -241,4 +241,14 @@ static inline void xen_preemptible_hcall_end(void) #endif /* CONFIG_PREEMPT */ +#if defined(CONFIG_XEN_PV) +pgd_t *xen_pv_kasan_early_init(void); +void xen_pv_kasan_pin_pgd(pgd_t *pgd); +void xen_pv_kasan_unpin_pgd(pgd_t *pgd); +#else +static inline pgd_t *xen_pv_kasan_early_init(void) { return NULL; } +static inline void xen_pv_kasan_pin_pgd(pgd_t *pgd) { } +static inline void xen_pv_kasan_unpin_pgd(pgd_t *pgd) { } +#endif /* defined(CONFIG_XEN_PV) */ + #endif /* INCLUDE_XEN_OPS_H */ diff --git a/kernel/Makefile b/kernel/Makefile index f2cc0d118a0b..1da6fd93c00c 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -12,6 +12,8 @@ obj-y = fork.o exec_domain.o panic.o \ notifier.o ksysfs.o cred.o reboot.o \ async.o range.o smpboot.o ucount.o +KASAN_SANITIZE_cpu.o := n + obj-$(CONFIG_MODULES) += kmod.o obj-$(CONFIG_MULTIUSER) += groups.o diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan index 81f5464ea9e1..429a638625ea 100644 --- a/lib/Kconfig.kasan +++ b/lib/Kconfig.kasan @@ -98,6 +98,7 @@ config KASAN_OUTLINE config KASAN_INLINE bool "Inline instrumentation" + depends on !XEN_PV help Compiler directly inserts code checking shadow memory before memory accesses. This is faster than outline (in some workloads @@ -147,7 +148,7 @@ config KASAN_SW_TAGS_IDENTIFY config KASAN_VMALLOC bool "Back mappings in vmalloc space with real shadow memory" - depends on KASAN && HAVE_ARCH_KASAN_VMALLOC + depends on KASAN && HAVE_ARCH_KASAN_VMALLOC && !XEN_PV help By default, the shadow region for vmalloc space is the read-only zero page. This means that KASAN cannot detect errors involving
This enables to use Outline instrumentation for Xen PV kernels. KASAN_INLINE and KASAN_VMALLOC options currently lead to boot crashes and hence disabled. Signed-off-by: Sergey Dyasli <sergey.dyasli@citrix.com> --- v1 --> v2: - Fix compilation without CONFIG_XEN_PV - Use macros for KASAN_SHADOW_START RFC --> v1: - New functions with declarations in xen/xen-ops.h - Fixed the issue with free_kernel_image_pages() with the help of xen_pv_kasan_unpin_pgd() --- arch/x86/mm/kasan_init_64.c | 12 ++++++++++++ arch/x86/xen/Makefile | 7 +++++++ arch/x86/xen/enlighten_pv.c | 3 +++ arch/x86/xen/mmu_pv.c | 38 +++++++++++++++++++++++++++++++++++++ drivers/xen/Makefile | 2 ++ include/xen/xen-ops.h | 10 ++++++++++ kernel/Makefile | 2 ++ lib/Kconfig.kasan | 3 ++- 8 files changed, 76 insertions(+), 1 deletion(-)