| Message ID | 20231103092954.238491-4-nrb@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | s390x: Add support for running guests without MSO/MSL | expand |
On 11/3/23 10:29, Nico Boehr wrote: > This is to prepare for running guests without MSO/MSL, which is > currently not possible. > > We already have code in sie64a to setup a guest primary ASCE before > entering SIE, so we can in theory switch to the page tables which > translate gpa to hpa. > > But the host is running in primary space mode already, so changing the > primary ASCE before entering SIE will also affect the host's code and > data. > > To make this switch useful, the host should run in a different address > space mode. Hence, set up and change to home address space mode before > installing the guest ASCE. > > The home space ASCE is just copied over from the primary space ASCE, so > no functional change is intended, also for tests that want to use > MSO/MSL. If a test intends to use a different primary space ASCE, it can > now just set the guest.asce in the save_area. > > Signed-off-by: Nico Boehr <nrb@linux.ibm.com> > Reviewed-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
On Fri, 3 Nov 2023 10:29:32 +0100 Nico Boehr <nrb@linux.ibm.com> wrote: > This is to prepare for running guests without MSO/MSL, which is > currently not possible. > > We already have code in sie64a to setup a guest primary ASCE before > entering SIE, so we can in theory switch to the page tables which > translate gpa to hpa. > > But the host is running in primary space mode already, so changing the > primary ASCE before entering SIE will also affect the host's code and > data. > > To make this switch useful, the host should run in a different address > space mode. Hence, set up and change to home address space mode before > installing the guest ASCE. > > The home space ASCE is just copied over from the primary space ASCE, so > no functional change is intended, also for tests that want to use > MSO/MSL. If a test intends to use a different primary space ASCE, it can > now just set the guest.asce in the save_area. > > Signed-off-by: Nico Boehr <nrb@linux.ibm.com> > Reviewed-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> > --- > lib/s390x/asm/arch_def.h | 1 + > lib/s390x/sie.c | 26 ++++++++++++++++++++++++++ > 2 files changed, 27 insertions(+) > > diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h > index 5beaf15b57e7..745a33878de5 100644 > --- a/lib/s390x/asm/arch_def.h > +++ b/lib/s390x/asm/arch_def.h > @@ -92,6 +92,7 @@ enum address_space { > }; > > #define PSW_MASK_DAT 0x0400000000000000UL > +#define PSW_MASK_HOME 0x0000C00000000000UL > #define PSW_MASK_IO 0x0200000000000000UL > #define PSW_MASK_EXT 0x0100000000000000UL > #define PSW_MASK_KEY 0x00F0000000000000UL > diff --git a/lib/s390x/sie.c b/lib/s390x/sie.c > index b44febdeaaac..7f4474555ff7 100644 > --- a/lib/s390x/sie.c > +++ b/lib/s390x/sie.c > @@ -52,6 +52,8 @@ void sie_handle_validity(struct vm *vm) > > void sie(struct vm *vm) > { > + uint64_t old_cr13; > + > if (vm->sblk->sdf == 2) > memcpy(vm->sblk->pv_grregs, vm->save_area.guest.grs, > sizeof(vm->save_area.guest.grs)); > @@ -59,6 +61,24 @@ void sie(struct vm *vm) > /* Reset icptcode so we don't trip over it below */ > vm->sblk->icptcode = 0; > > + /* > + * Set up home address space to match primary space. Instead of running > + * in home space all the time, we switch every time in sie() because: > + * - tests that depend on running in primary space mode don't need to be > + * touched > + * - it avoids regressions in tests > + * - switching every time makes it easier to extend this in the future, > + * for example to allow tests to run in whatever space they want > + */ > + old_cr13 = stctg(13); > + lctlg(13, stctg(1)); > + > + /* switch to home space so guest tables can be different from host */ > + psw_mask_set_bits(PSW_MASK_HOME); > + > + /* also handle all interruptions in home space while in SIE */ > + irq_set_dat_mode(true, AS_HOME); > + > while (vm->sblk->icptcode == 0) { > sie64a(vm->sblk, &vm->save_area); > sie_handle_validity(vm); > @@ -66,6 +86,12 @@ void sie(struct vm *vm) > vm->save_area.guest.grs[14] = vm->sblk->gg14; > vm->save_area.guest.grs[15] = vm->sblk->gg15; > > + irq_set_dat_mode(true, AS_PRIM); > + psw_mask_clear_bits(PSW_MASK_HOME); > + > + /* restore the old CR 13 */ > + lctlg(13, old_cr13); > + > if (vm->sblk->sdf == 2) > memcpy(vm->save_area.guest.grs, vm->sblk->pv_grregs, > sizeof(vm->save_area.guest.grs));
diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h index 5beaf15b57e7..745a33878de5 100644 --- a/lib/s390x/asm/arch_def.h +++ b/lib/s390x/asm/arch_def.h @@ -92,6 +92,7 @@ enum address_space { }; #define PSW_MASK_DAT 0x0400000000000000UL +#define PSW_MASK_HOME 0x0000C00000000000UL #define PSW_MASK_IO 0x0200000000000000UL #define PSW_MASK_EXT 0x0100000000000000UL #define PSW_MASK_KEY 0x00F0000000000000UL diff --git a/lib/s390x/sie.c b/lib/s390x/sie.c index b44febdeaaac..7f4474555ff7 100644 --- a/lib/s390x/sie.c +++ b/lib/s390x/sie.c @@ -52,6 +52,8 @@ void sie_handle_validity(struct vm *vm) void sie(struct vm *vm) { + uint64_t old_cr13; + if (vm->sblk->sdf == 2) memcpy(vm->sblk->pv_grregs, vm->save_area.guest.grs, sizeof(vm->save_area.guest.grs)); @@ -59,6 +61,24 @@ void sie(struct vm *vm) /* Reset icptcode so we don't trip over it below */ vm->sblk->icptcode = 0; + /* + * Set up home address space to match primary space. Instead of running + * in home space all the time, we switch every time in sie() because: + * - tests that depend on running in primary space mode don't need to be + * touched + * - it avoids regressions in tests + * - switching every time makes it easier to extend this in the future, + * for example to allow tests to run in whatever space they want + */ + old_cr13 = stctg(13); + lctlg(13, stctg(1)); + + /* switch to home space so guest tables can be different from host */ + psw_mask_set_bits(PSW_MASK_HOME); + + /* also handle all interruptions in home space while in SIE */ + irq_set_dat_mode(true, AS_HOME); + while (vm->sblk->icptcode == 0) { sie64a(vm->sblk, &vm->save_area); sie_handle_validity(vm); @@ -66,6 +86,12 @@ void sie(struct vm *vm) vm->save_area.guest.grs[14] = vm->sblk->gg14; vm->save_area.guest.grs[15] = vm->sblk->gg15; + irq_set_dat_mode(true, AS_PRIM); + psw_mask_clear_bits(PSW_MASK_HOME); + + /* restore the old CR 13 */ + lctlg(13, old_cr13); + if (vm->sblk->sdf == 2) memcpy(vm->save_area.guest.grs, vm->sblk->pv_grregs, sizeof(vm->save_area.guest.grs));