| Message ID | 20240412084309.1733783-5-steven.price@arm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2,01/43] KVM: Prepare for handling only shared mappings in mmu_notifier events | expand |
On 12/04/2024 09:42, Steven Price wrote: > If the host attempts to access granules that have been delegated for use > in a realm these accesses will be caught and will trigger a Granule > Protection Fault (GPF). > > A fault during a page walk signals a bug in the kernel and is handled by > oopsing the kernel. A non-page walk fault could be caused by user space > having access to a page which has been delegated to the kernel and will > trigger a SIGBUS to allow debugging why user space is trying to access a > delegated page. > > Signed-off-by: Steven Price <steven.price@arm.com> > --- > arch/arm64/mm/fault.c | 29 ++++++++++++++++++++++++----- > 1 file changed, 24 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index 8251e2fea9c7..91da0f446dd9 100644 > --- a/arch/arm64/mm/fault.c > +++ b/arch/arm64/mm/fault.c > @@ -765,6 +765,25 @@ static int do_tag_check_fault(unsigned long far, unsigned long esr, > return 0; > } > > +static int do_gpf_ptw(unsigned long far, unsigned long esr, struct pt_regs *regs) > +{ > + const struct fault_info *inf = esr_to_fault_info(esr); > + > + die_kernel_fault(inf->name, far, esr, regs); > + return 0; > +} > + > +static int do_gpf(unsigned long far, unsigned long esr, struct pt_regs *regs) > +{ > + const struct fault_info *inf = esr_to_fault_info(esr); > + > + if (!is_el1_instruction_abort(esr) && fixup_exception(regs)) > + return 0; > + > + arm64_notify_die(inf->name, regs, inf->sig, inf->code, far, esr); > + return 0; > +} > + > static const struct fault_info fault_info[] = { > { do_bad, SIGKILL, SI_KERNEL, "ttbr address size fault" }, > { do_bad, SIGKILL, SI_KERNEL, "level 1 address size fault" }, > @@ -802,11 +821,11 @@ static const struct fault_info fault_info[] = { > { do_alignment_fault, SIGBUS, BUS_ADRALN, "alignment fault" }, > { do_bad, SIGKILL, SI_KERNEL, "unknown 34" }, > { do_bad, SIGKILL, SI_KERNEL, "unknown 35" }, Should this also be converted to do_gpf_ptw, "GPF at level -1", given we support LPA2 ? > - { do_bad, SIGKILL, SI_KERNEL, "unknown 36" }, > - { do_bad, SIGKILL, SI_KERNEL, "unknown 37" }, > - { do_bad, SIGKILL, SI_KERNEL, "unknown 38" }, > - { do_bad, SIGKILL, SI_KERNEL, "unknown 39" }, > - { do_bad, SIGKILL, SI_KERNEL, "unknown 40" }, > + { do_gpf_ptw, SIGKILL, SI_KERNEL, "Granule Protection Fault at level 0" }, > + { do_gpf_ptw, SIGKILL, SI_KERNEL, "Granule Protection Fault at level 1" }, > + { do_gpf_ptw, SIGKILL, SI_KERNEL, "Granule Protection Fault at level 2" }, > + { do_gpf_ptw, SIGKILL, SI_KERNEL, "Granule Protection Fault at level 3" }, > + { do_gpf, SIGBUS, SI_KERNEL, "Granule Protection Fault not on table walk" }, > { do_bad, SIGKILL, SI_KERNEL, "level -1 address size fault" }, > { do_bad, SIGKILL, SI_KERNEL, "unknown 42" }, > { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level -1 translation fault" }, Rest looks fine to me. Suzuki
On 16/04/2024 12:17, Suzuki K Poulose wrote: > On 12/04/2024 09:42, Steven Price wrote: >> If the host attempts to access granules that have been delegated for use >> in a realm these accesses will be caught and will trigger a Granule >> Protection Fault (GPF). >> >> A fault during a page walk signals a bug in the kernel and is handled by >> oopsing the kernel. A non-page walk fault could be caused by user space >> having access to a page which has been delegated to the kernel and will >> trigger a SIGBUS to allow debugging why user space is trying to access a >> delegated page. >> >> Signed-off-by: Steven Price <steven.price@arm.com> >> --- >> arch/arm64/mm/fault.c | 29 ++++++++++++++++++++++++----- >> 1 file changed, 24 insertions(+), 5 deletions(-) >> >> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c >> index 8251e2fea9c7..91da0f446dd9 100644 >> --- a/arch/arm64/mm/fault.c >> +++ b/arch/arm64/mm/fault.c >> @@ -765,6 +765,25 @@ static int do_tag_check_fault(unsigned long far, >> unsigned long esr, >> return 0; >> } >> +static int do_gpf_ptw(unsigned long far, unsigned long esr, struct >> pt_regs *regs) >> +{ >> + const struct fault_info *inf = esr_to_fault_info(esr); >> + >> + die_kernel_fault(inf->name, far, esr, regs); >> + return 0; >> +} >> + >> +static int do_gpf(unsigned long far, unsigned long esr, struct >> pt_regs *regs) >> +{ >> + const struct fault_info *inf = esr_to_fault_info(esr); >> + >> + if (!is_el1_instruction_abort(esr) && fixup_exception(regs)) >> + return 0; >> + >> + arm64_notify_die(inf->name, regs, inf->sig, inf->code, far, esr); >> + return 0; >> +} >> + >> static const struct fault_info fault_info[] = { >> { do_bad, SIGKILL, SI_KERNEL, "ttbr address size >> fault" }, >> { do_bad, SIGKILL, SI_KERNEL, "level 1 address size >> fault" }, >> @@ -802,11 +821,11 @@ static const struct fault_info fault_info[] = { >> { do_alignment_fault, SIGBUS, BUS_ADRALN, "alignment >> fault" }, >> { do_bad, SIGKILL, SI_KERNEL, "unknown 34" }, >> { do_bad, SIGKILL, SI_KERNEL, "unknown 35" }, > > Should this also be converted to do_gpf_ptw, "GPF at level -1", given we > support LPA2 ? Ah, yes I somehow missed that. Although something has gone majorly wrong if this triggers! ;) Steve >> - { do_bad, SIGKILL, SI_KERNEL, "unknown 36" }, >> - { do_bad, SIGKILL, SI_KERNEL, "unknown 37" }, >> - { do_bad, SIGKILL, SI_KERNEL, "unknown 38" }, >> - { do_bad, SIGKILL, SI_KERNEL, "unknown 39" }, >> - { do_bad, SIGKILL, SI_KERNEL, "unknown 40" }, >> + { do_gpf_ptw, SIGKILL, SI_KERNEL, "Granule Protection >> Fault at level 0" }, >> + { do_gpf_ptw, SIGKILL, SI_KERNEL, "Granule Protection >> Fault at level 1" }, >> + { do_gpf_ptw, SIGKILL, SI_KERNEL, "Granule Protection >> Fault at level 2" }, >> + { do_gpf_ptw, SIGKILL, SI_KERNEL, "Granule Protection >> Fault at level 3" }, >> + { do_gpf, SIGBUS, SI_KERNEL, "Granule Protection Fault >> not on table walk" }, >> { do_bad, SIGKILL, SI_KERNEL, "level -1 address size >> fault" }, >> { do_bad, SIGKILL, SI_KERNEL, "unknown 42" }, >> { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level -1 >> translation fault" }, > > > Rest looks fine to me. > > Suzuki
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 8251e2fea9c7..91da0f446dd9 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -765,6 +765,25 @@ static int do_tag_check_fault(unsigned long far, unsigned long esr, return 0; } +static int do_gpf_ptw(unsigned long far, unsigned long esr, struct pt_regs *regs) +{ + const struct fault_info *inf = esr_to_fault_info(esr); + + die_kernel_fault(inf->name, far, esr, regs); + return 0; +} + +static int do_gpf(unsigned long far, unsigned long esr, struct pt_regs *regs) +{ + const struct fault_info *inf = esr_to_fault_info(esr); + + if (!is_el1_instruction_abort(esr) && fixup_exception(regs)) + return 0; + + arm64_notify_die(inf->name, regs, inf->sig, inf->code, far, esr); + return 0; +} + static const struct fault_info fault_info[] = { { do_bad, SIGKILL, SI_KERNEL, "ttbr address size fault" }, { do_bad, SIGKILL, SI_KERNEL, "level 1 address size fault" }, @@ -802,11 +821,11 @@ static const struct fault_info fault_info[] = { { do_alignment_fault, SIGBUS, BUS_ADRALN, "alignment fault" }, { do_bad, SIGKILL, SI_KERNEL, "unknown 34" }, { do_bad, SIGKILL, SI_KERNEL, "unknown 35" }, - { do_bad, SIGKILL, SI_KERNEL, "unknown 36" }, - { do_bad, SIGKILL, SI_KERNEL, "unknown 37" }, - { do_bad, SIGKILL, SI_KERNEL, "unknown 38" }, - { do_bad, SIGKILL, SI_KERNEL, "unknown 39" }, - { do_bad, SIGKILL, SI_KERNEL, "unknown 40" }, + { do_gpf_ptw, SIGKILL, SI_KERNEL, "Granule Protection Fault at level 0" }, + { do_gpf_ptw, SIGKILL, SI_KERNEL, "Granule Protection Fault at level 1" }, + { do_gpf_ptw, SIGKILL, SI_KERNEL, "Granule Protection Fault at level 2" }, + { do_gpf_ptw, SIGKILL, SI_KERNEL, "Granule Protection Fault at level 3" }, + { do_gpf, SIGBUS, SI_KERNEL, "Granule Protection Fault not on table walk" }, { do_bad, SIGKILL, SI_KERNEL, "level -1 address size fault" }, { do_bad, SIGKILL, SI_KERNEL, "unknown 42" }, { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level -1 translation fault" },
If the host attempts to access granules that have been delegated for use in a realm these accesses will be caught and will trigger a Granule Protection Fault (GPF). A fault during a page walk signals a bug in the kernel and is handled by oopsing the kernel. A non-page walk fault could be caused by user space having access to a page which has been delegated to the kernel and will trigger a SIGBUS to allow debugging why user space is trying to access a delegated page. Signed-off-by: Steven Price <steven.price@arm.com> --- arch/arm64/mm/fault.c | 29 ++++++++++++++++++++++++----- 1 file changed, 24 insertions(+), 5 deletions(-)