| Message ID | 20190103100806.9039-5-frankja@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | 390x: Add cross hypervisor and disk boot | expand |
On 2019-01-03 11:07, Janosch Frank wrote: > LPAR and z/VM start in esam mode depending on the hardware, so we need > to switch to z/Arch and set 64 bit addressing. > > Under Qemu/KVM we already start out with both when being run with the > Qemu --kernel argument or we lack 64 bit when booting from disk > because of the initial psw specifying 31 bit for z/VM and lpar > compatibility. > > Signed-off-by: Janosch Frank <frankja@linux.ibm.com> > Reviewed-by: David Hildenbrand <david@redhat.com> > --- > s390x/cstart64.S | 10 ++++++++++ > 1 file changed, 10 insertions(+) Reviewed-by: Thomas Huth <thuth@redhat.com>
On 03.01.19 13:37, Thomas Huth wrote: > On 2019-01-03 11:07, Janosch Frank wrote: >> LPAR and z/VM start in esam mode depending on the hardware, so we need >> to switch to z/Arch and set 64 bit addressing. >> >> Under Qemu/KVM we already start out with both when being run with the >> Qemu --kernel argument or we lack 64 bit when booting from disk >> because of the initial psw specifying 31 bit for z/VM and lpar >> compatibility. >> >> Signed-off-by: Janosch Frank <frankja@linux.ibm.com> >> Reviewed-by: David Hildenbrand <david@redhat.com> >> --- >> s390x/cstart64.S | 10 ++++++++++ >> 1 file changed, 10 insertions(+) > > Reviewed-by: Thomas Huth <thuth@redhat.com> > Thanks! The title will be changed to: s390x: Switch to z/Arch and enable 64 bit addressing mode Also I will move the sam64 from the previous patch into this one.
Hi Janosch, happy new year! On 03.01.2019 11:07, Janosch Frank wrote: > LPAR and z/VM start in esam mode depending on the hardware, so we need Did you consider the CZAM facility? You already use a so called "short PSW" (which is compatible to the ESA/390 PSW, as you did not set bit 31). LPAR and z/VM start in esam or esame mode, depending on the hardware CZAM facility and z/VM MACHINE setting. See POP section "Load State": "When neither the configuration-z/Architecture-architectural-mode (CZAM) facility nor the ESA/390-compatibility-mode facility are installed, this sets the architectural mode to the ESA/390 mode. When the ESA/390-compatibility-mode facility is installed, this sets the architecture mode to the ESA/390-compatibility mode. When the CZAM facility is installed, the architectural mode is unchanged (that is, it remains in the z/Architecture architectural mode)." > to switch to z/Arch and set 64 bit addressing. Wouldn't it be nice to mention this in the commit subject: s390x: Switch to z/Arch and 64-bit addressing [mode] > Under Qemu/KVM we already start out with both when being run with the > Qemu --kernel argument or we lack 64 bit when booting from disk > because of the initial psw specifying 31 bit for z/VM and lpar > compatibility. > > Signed-off-by: Janosch Frank <frankja@linux.ibm.com> > Reviewed-by: David Hildenbrand <david@redhat.com> > --- > s390x/cstart64.S | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/s390x/cstart64.S b/s390x/cstart64.S > index d382497..6622633 100644 > --- a/s390x/cstart64.S > +++ b/s390x/cstart64.S > @@ -11,6 +11,7 @@ > * under the terms of the GNU Library General Public License version 2. > */ > #include <asm/asm-offsets.h> > +#include <asm/sigp.h> > > .section .init > > @@ -20,9 +21,18 @@ > * > * For KVM and TCG kernel boot we are in 64 bit z/Arch mode. > * When booting from disk the initial short psw is in 31 bit mode. > + * When running under LPAR or z/VM, we might start in 31 bit and esam mode. > */ > .globl start > start: > + /* Switch to z/Architecture mode and 64-bit */ > + slr %r0, %r0 # Set cpuid to zero > + lhi %r1, 2 # mode 2 = esame > + sigp %r1, %r0, SIGP_SET_ARCHITECTURE > + /* XOR all registers with themselves to clear them fully. */ > + .irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 > + xgr \i,\i > + .endr > sam64 # Set addressing mode to 64 bit > /* setup stack */ > larl %r15, stackptr > Regards, Jens
On 04.01.19 09:56, Jens Remus wrote: > Hi Janosch, > > happy new year! Thanks, same to you. > > On 03.01.2019 11:07, Janosch Frank wrote: >> LPAR and z/VM start in esam mode depending on the hardware, so we need > > Did you consider the CZAM facility? You already use a so called "short > PSW" (which is compatible to the ESA/390 PSW, as you did not set bit 31). > > LPAR and z/VM start in esam or esame mode, depending on the hardware > CZAM facility and z/VM MACHINE setting. > > See POP section "Load State": > > "When neither the configuration-z/Architecture-architectural-mode (CZAM) > facility nor the ESA/390-compatibility-mode facility are installed, this > sets the architectural mode to the ESA/390 mode. When the > ESA/390-compatibility-mode facility is installed, this sets the > architecture mode to the ESA/390-compatibility mode. When the CZAM > facility is installed, the architectural mode is unchanged (that is, it > remains in the z/Architecture architectural mode)." > >> to switch to z/Arch and set 64 bit addressing. I don't really want to test in which state I am and blindly setting z/Arch and 64 bit is a valid course of action according to the AR. > > Wouldn't it be nice to mention this in the commit subject: > > s390x: Switch to z/Arch and 64-bit addressing [mode] As commented yesterday (Message-ID: <9644d7ab-d815-720d-f1a1-eee1a6a0c253@linux.ibm.com>): The title will be changed to: s390x: Switch to z/Arch and enable 64 bit addressing mode Also I will move the sam64 from the previous patch into this one. I might add to the comment that we do this no matter what configuration we start out in, because it doesn't produce an exception.
Hello Janosch! On 04.01.2019 11:15, Janosch Frank wrote: > On 04.01.19 09:56, Jens Remus wrote: >> Hi Janosch, >> >> happy new year! > > Thanks, same to you. > >> >> On 03.01.2019 11:07, Janosch Frank wrote: >>> LPAR and z/VM start in esam mode depending on the hardware, so we need >> >> Did you consider the CZAM facility? You already use a so called "short >> PSW" (which is compatible to the ESA/390 PSW, as you did not set bit 31). >> >> LPAR and z/VM start in esam or esame mode, depending on the hardware >> CZAM facility and z/VM MACHINE setting. >> >> See POP section "Load State": >> >> "When neither the configuration-z/Architecture-architectural-mode (CZAM) >> facility nor the ESA/390-compatibility-mode facility are installed, this >> sets the architectural mode to the ESA/390 mode. When the >> ESA/390-compatibility-mode facility is installed, this sets the >> architecture mode to the ESA/390-compatibility mode. When the CZAM >> facility is installed, the architectural mode is unchanged (that is, it >> remains in the z/Architecture architectural mode)." >> >>> to switch to z/Arch and set 64 bit addressing. > > I don't really want to test in which state I am and blindly setting > z/Arch and 64 bit is a valid course of action according to the AR. I completely agree with you. I was rather thinking of enhancing the commit message to make clear that LPAR and z/VM start either in esam or esame mode, depending on the hardware CZAM facility and z/VM MACHINE setting. Re-reading your commit message I must admit that it kind of already contains this with "depending on the hardware" and one may then deduct from the commit subject that it must be z/Arch (esame) otherwise. >> Wouldn't it be nice to mention this in the commit subject: >> >> s390x: Switch to z/Arch and 64-bit addressing [mode] > > As commented yesterday (Message-ID: > <9644d7ab-d815-720d-f1a1-eee1a6a0c253@linux.ibm.com>): > The title will be changed to: > s390x: Switch to z/Arch and enable 64 bit addressing mode > > Also I will move the sam64 from the previous patch into this one. > > > I might add to the comment that we do this no matter what configuration > we start out in, because it doesn't produce an exception. That would be nice. Thanks! Regards, Jens
diff --git a/s390x/cstart64.S b/s390x/cstart64.S index d382497..6622633 100644 --- a/s390x/cstart64.S +++ b/s390x/cstart64.S @@ -11,6 +11,7 @@ * under the terms of the GNU Library General Public License version 2. */ #include <asm/asm-offsets.h> +#include <asm/sigp.h> .section .init @@ -20,9 +21,18 @@ * * For KVM and TCG kernel boot we are in 64 bit z/Arch mode. * When booting from disk the initial short psw is in 31 bit mode. + * When running under LPAR or z/VM, we might start in 31 bit and esam mode. */ .globl start start: + /* Switch to z/Architecture mode and 64-bit */ + slr %r0, %r0 # Set cpuid to zero + lhi %r1, 2 # mode 2 = esame + sigp %r1, %r0, SIGP_SET_ARCHITECTURE + /* XOR all registers with themselves to clear them fully. */ + .irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 + xgr \i,\i + .endr sam64 # Set addressing mode to 64 bit /* setup stack */ larl %r15, stackptr