| Message ID | 20220615193116.806312-3-coltonlewis@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Fix filename reporting in guest asserts | expand |
On Wed, Jun 15, 2022 at 07:31:14PM +0000, Colton Lewis wrote: > Increase UCALL_MAX_ARGS to 7 to allow GUEST_ASSERT_4 to pass 3 builtin > ucall arguments specified in guest_assert_builtin_args plus 4 > user-specified arguments. > > Signed-off-by: Colton Lewis <coltonlewis@google.com> > --- > tools/testing/selftests/kvm/include/ucall_common.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/testing/selftests/kvm/include/ucall_common.h b/tools/testing/selftests/kvm/include/ucall_common.h > index dbe872870b83..568c562f14cd 100644 > --- a/tools/testing/selftests/kvm/include/ucall_common.h > +++ b/tools/testing/selftests/kvm/include/ucall_common.h > @@ -16,7 +16,7 @@ enum { > UCALL_UNHANDLED, > }; > > -#define UCALL_MAX_ARGS 6 > +#define UCALL_MAX_ARGS 7 > > struct ucall { > uint64_t cmd; > -- > 2.36.1.476.g0c4daa206d-goog > We probably want to ensure all architectures are good with this. afaict, riscv only expects 6 args and uses UCALL_MAX_ARGS to cap the ucall inputs, for example. Thanks, drew
On Thu, Jun 16, 2022 at 02:10:06PM +0200, Andrew Jones wrote: > We probably want to ensure all architectures are good with this. afaict, > riscv only expects 6 args and uses UCALL_MAX_ARGS to cap the ucall inputs, > for example. All architectures use UCALL_MAX_ARGS for that. Are you saying there might be limitations beyond the value of the macro? If so, who should verify whether this is ok?
On Fri, Jun 17, 2022, Colton Lewis wrote: > On Thu, Jun 16, 2022 at 02:10:06PM +0200, Andrew Jones wrote: > > We probably want to ensure all architectures are good with this. afaict, > > riscv only expects 6 args and uses UCALL_MAX_ARGS to cap the ucall inputs, > > for example. > > All architectures use UCALL_MAX_ARGS for that. Are you saying there > might be limitations beyond the value of the macro? If so, who should > verify whether this is ok? I thought there were architectural limitations too, but I believe I was thinking of vcpu_args_set(), where the number of params is limited by the function call ABI, e.g. the number of registers. Unless there's something really, really subtle going on, all architectures pass the actual ucall struct purely through memory. Actually, that code is ripe for deduplication, and amazingly it doesn't conflict with Colton's series. Patches incoming...
On Sat, Jun 18, 2022 at 12:09:11AM +0000, Sean Christopherson wrote: > On Fri, Jun 17, 2022, Colton Lewis wrote: > > On Thu, Jun 16, 2022 at 02:10:06PM +0200, Andrew Jones wrote: > > > We probably want to ensure all architectures are good with this. afaict, > > > riscv only expects 6 args and uses UCALL_MAX_ARGS to cap the ucall inputs, > > > for example. > > > > All architectures use UCALL_MAX_ARGS for that. Are you saying there > > might be limitations beyond the value of the macro? If so, who should > > verify whether this is ok? > > I thought there were architectural limitations too, but I believe I was thinking > of vcpu_args_set(), where the number of params is limited by the function call > ABI, e.g. the number of registers. > > Unless there's something really, really subtle going on, all architectures pass > the actual ucall struct purely through memory. Actually, that code is ripe for > deduplication, and amazingly it doesn't conflict with Colton's series. Patches > incoming... > RISC-V uses sbi_ecall() for their implementation of ucall(). CC'ing Anup for confirmation, but if I understand the SBI spec correctly, then inputs are limited to registers a0-a5. Thanks, drew
On Mon, Jun 20, 2022 at 12:51 PM Andrew Jones <drjones@redhat.com> wrote: > > On Sat, Jun 18, 2022 at 12:09:11AM +0000, Sean Christopherson wrote: > > On Fri, Jun 17, 2022, Colton Lewis wrote: > > > On Thu, Jun 16, 2022 at 02:10:06PM +0200, Andrew Jones wrote: > > > > We probably want to ensure all architectures are good with this. afaict, > > > > riscv only expects 6 args and uses UCALL_MAX_ARGS to cap the ucall inputs, > > > > for example. > > > > > > All architectures use UCALL_MAX_ARGS for that. Are you saying there > > > might be limitations beyond the value of the macro? If so, who should > > > verify whether this is ok? > > > > I thought there were architectural limitations too, but I believe I was thinking > > of vcpu_args_set(), where the number of params is limited by the function call > > ABI, e.g. the number of registers. > > > > Unless there's something really, really subtle going on, all architectures pass > > the actual ucall struct purely through memory. Actually, that code is ripe for > > deduplication, and amazingly it doesn't conflict with Colton's series. Patches > > incoming... > > > > RISC-V uses sbi_ecall() for their implementation of ucall(). CC'ing Anup > for confirmation, but if I understand the SBI spec correctly, then inputs > are limited to registers a0-a5. Yes, we only have 6 parameters in ucall() since it is based on SBI spec. Actually, a6 and a7 are used to identify the type of SBI call (i.e. extension and function number) whereas a0-a5 are function parameters. Regards, Anup > > Thanks, > drew >
On Mon, Jun 20, 2022 at 09:21:11AM +0200, Andrew Jones wrote: > On Sat, Jun 18, 2022 at 12:09:11AM +0000, Sean Christopherson wrote: > > On Fri, Jun 17, 2022, Colton Lewis wrote: > > > On Thu, Jun 16, 2022 at 02:10:06PM +0200, Andrew Jones wrote: > > > > We probably want to ensure all architectures are good with this. afaict, > > > > riscv only expects 6 args and uses UCALL_MAX_ARGS to cap the ucall inputs, > > > > for example. > > > > > > All architectures use UCALL_MAX_ARGS for that. Are you saying there > > > might be limitations beyond the value of the macro? If so, who should > > > verify whether this is ok? > > > > I thought there were architectural limitations too, but I believe I was thinking > > of vcpu_args_set(), where the number of params is limited by the function call > > ABI, e.g. the number of registers. > > > > Unless there's something really, really subtle going on, all architectures pass > > the actual ucall struct purely through memory. Actually, that code is ripe for > > deduplication, and amazingly it doesn't conflict with Colton's series. Patches > > incoming... > > > > RISC-V uses sbi_ecall() for their implementation of ucall(). CC'ing Anup > for confirmation, but if I understand the SBI spec correctly, then inputs > are limited to registers a0-a5. Ah, never mind... I see SBI is limited to 6 registers, but of course it only needs one register to pass the uc address... We can make UCALL_MAX_ARGS whatever we want. Thanks, drew
On Wed, Jun 15, 2022 at 07:31:14PM +0000, Colton Lewis wrote: > Increase UCALL_MAX_ARGS to 7 to allow GUEST_ASSERT_4 to pass 3 builtin > ucall arguments specified in guest_assert_builtin_args plus 4 > user-specified arguments. > > Signed-off-by: Colton Lewis <coltonlewis@google.com> > --- > tools/testing/selftests/kvm/include/ucall_common.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/testing/selftests/kvm/include/ucall_common.h b/tools/testing/selftests/kvm/include/ucall_common.h > index dbe872870b83..568c562f14cd 100644 > --- a/tools/testing/selftests/kvm/include/ucall_common.h > +++ b/tools/testing/selftests/kvm/include/ucall_common.h > @@ -16,7 +16,7 @@ enum { > UCALL_UNHANDLED, > }; > > -#define UCALL_MAX_ARGS 6 > +#define UCALL_MAX_ARGS 7 > > struct ucall { > uint64_t cmd; > -- > 2.36.1.476.g0c4daa206d-goog > Reviewed-by: Andrew Jones <drjones@redhat.com>
diff --git a/tools/testing/selftests/kvm/include/ucall_common.h b/tools/testing/selftests/kvm/include/ucall_common.h index dbe872870b83..568c562f14cd 100644 --- a/tools/testing/selftests/kvm/include/ucall_common.h +++ b/tools/testing/selftests/kvm/include/ucall_common.h @@ -16,7 +16,7 @@ enum { UCALL_UNHANDLED, }; -#define UCALL_MAX_ARGS 6 +#define UCALL_MAX_ARGS 7 struct ucall { uint64_t cmd;
Increase UCALL_MAX_ARGS to 7 to allow GUEST_ASSERT_4 to pass 3 builtin ucall arguments specified in guest_assert_builtin_args plus 4 user-specified arguments. Signed-off-by: Colton Lewis <coltonlewis@google.com> --- tools/testing/selftests/kvm/include/ucall_common.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)