Re: [PATCH v6 13/13] s390: Recognize confidential-guest-support option
On Wed, Jan 13, 2021 at 07:57:41AM +0100, Christian Borntraeger wrote:
>
>
> On 13.01.21 01:57, David Gibson wrote:
> > On Tue, Jan 12, 2021 at 12:36:07PM +0100, Cornelia Huck wrote:
> > 65;6201;1c> On Tue, 12 Jan 2021 09:15:26 +0100
> >> Christian Borntraeger wrote:
> >>
> >>> On 12.01.21 05:45, David Gibson wrote:
> At least some s390 cpu models support "Protected Virtualization" (PV),
> a mechanism to protect guests from eavesdropping by a compromised
> hypervisor.
>
> This is similar in function to other mechanisms like AMD's SEV and
> POWER's PEF, which are controlled by the "confidential-guest-support"
> machine option. s390 is a slightly special case, because we already
> supported PV, simply by using a CPU model with the required feature
> (S390_FEAT_UNPACK).
>
> To integrate this with the option used by other platforms, we
> implement the following compromise:
>
> - When the confidential-guest-support option is set, s390 will
> recognize it, verify that the CPU can support PV (failing if not)
> and set virtio default options necessary for encrypted or protected
> guests, as on other platforms. i.e. if confidential-guest-support
> is set, we will either create a guest capable of entering PV mode,
> or fail outright.
>
> - If confidential-guest-support is not set, guests might still be
> able to enter PV mode, if the CPU has the right model. This may be
> a little surprising, but shouldn't actually be harmful.
>
> To start a guest supporting Protected Virtualization using the new
> option use the command line arguments:
> -object s390-pv-guest,id=pv0 -machine confidential-guest-support=pv0
>
> >>>
> >>>
> >>> This results in
> >>>
> >>> [cborntra@t35lp61 qemu]$ qemu-system-s390x -enable-kvm -nographic -m 2G
> >>> -kernel ~/full.normal
> >>> **
> >>> ERROR:../qom/object.c:317:type_initialize: assertion failed:
> >>> (parent->instance_size <= ti->instance_size)
> >>> Bail out! ERROR:../qom/object.c:317:type_initialize: assertion failed:
> >>> (parent->instance_size <= ti->instance_size)
> >>> Aborted (core dumped)
> >>>
> >>
> +static const TypeInfo s390_pv_guest_info = {
> +.parent = TYPE_CONFIDENTIAL_GUEST_SUPPORT,
> +.name = TYPE_S390_PV_GUEST,
> +.instance_size = sizeof(S390PVGuestState),
> +.interfaces = (InterfaceInfo[]) {
> +{ TYPE_USER_CREATABLE },
> +{ }
> +}
> +};
> >>
> >> I think this needs TYPE_OBJECT in .parent and
> >> TYPE_CONFIDENTIAL_GUEST_SUPPORT as an interface to fix the crash.
> >
> > No, that was true of an earlier revision, but parent is correct in the
> > current version.
>
> right now parent is obviously wrong as it triggers the above warning (and all
> other
> variants in the previous patches also use TYPE_OBJECT). It is probably the
> right
> thing when you fix
>
> +struct S390PVGuestState {
> +Object parent_obj;
> +};
> +
>
> and change Object to the proper type I guess.
Yes, I think so. In the next spin I've fixed the parent_obj field (as
well as moving to OBJECT_DEFINE_TYPE()) and it's passing the gitlab
CI, at least.
--
David Gibson| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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Re: [PATCH v6 13/13] s390: Recognize confidential-guest-support option
On 13.01.21 01:57, David Gibson wrote:
> On Tue, Jan 12, 2021 at 12:36:07PM +0100, Cornelia Huck wrote:
> 65;6201;1c> On Tue, 12 Jan 2021 09:15:26 +0100
>> Christian Borntraeger wrote:
>>
>>> On 12.01.21 05:45, David Gibson wrote:
At least some s390 cpu models support "Protected Virtualization" (PV),
a mechanism to protect guests from eavesdropping by a compromised
hypervisor.
This is similar in function to other mechanisms like AMD's SEV and
POWER's PEF, which are controlled by the "confidential-guest-support"
machine option. s390 is a slightly special case, because we already
supported PV, simply by using a CPU model with the required feature
(S390_FEAT_UNPACK).
To integrate this with the option used by other platforms, we
implement the following compromise:
- When the confidential-guest-support option is set, s390 will
recognize it, verify that the CPU can support PV (failing if not)
and set virtio default options necessary for encrypted or protected
guests, as on other platforms. i.e. if confidential-guest-support
is set, we will either create a guest capable of entering PV mode,
or fail outright.
- If confidential-guest-support is not set, guests might still be
able to enter PV mode, if the CPU has the right model. This may be
a little surprising, but shouldn't actually be harmful.
To start a guest supporting Protected Virtualization using the new
option use the command line arguments:
-object s390-pv-guest,id=pv0 -machine confidential-guest-support=pv0
>>>
>>>
>>> This results in
>>>
>>> [cborntra@t35lp61 qemu]$ qemu-system-s390x -enable-kvm -nographic -m 2G
>>> -kernel ~/full.normal
>>> **
>>> ERROR:../qom/object.c:317:type_initialize: assertion failed:
>>> (parent->instance_size <= ti->instance_size)
>>> Bail out! ERROR:../qom/object.c:317:type_initialize: assertion failed:
>>> (parent->instance_size <= ti->instance_size)
>>> Aborted (core dumped)
>>>
>>
+static const TypeInfo s390_pv_guest_info = {
+.parent = TYPE_CONFIDENTIAL_GUEST_SUPPORT,
+.name = TYPE_S390_PV_GUEST,
+.instance_size = sizeof(S390PVGuestState),
+.interfaces = (InterfaceInfo[]) {
+{ TYPE_USER_CREATABLE },
+{ }
+}
+};
>>
>> I think this needs TYPE_OBJECT in .parent and
>> TYPE_CONFIDENTIAL_GUEST_SUPPORT as an interface to fix the crash.
>
> No, that was true of an earlier revision, but parent is correct in the
> current version.
right now parent is obviously wrong as it triggers the above warning (and all
other
variants in the previous patches also use TYPE_OBJECT). It is probably the right
thing when you fix
+struct S390PVGuestState {
+Object parent_obj;
+};
+
and change Object to the proper type I guess.
Re: [PATCH v6 13/13] s390: Recognize confidential-guest-support option
On Tue, Jan 12, 2021 at 12:36:07PM +0100, Cornelia Huck wrote:
65;6201;1c> On Tue, 12 Jan 2021 09:15:26 +0100
> Christian Borntraeger wrote:
>
> > On 12.01.21 05:45, David Gibson wrote:
> > > At least some s390 cpu models support "Protected Virtualization" (PV),
> > > a mechanism to protect guests from eavesdropping by a compromised
> > > hypervisor.
> > >
> > > This is similar in function to other mechanisms like AMD's SEV and
> > > POWER's PEF, which are controlled by the "confidential-guest-support"
> > > machine option. s390 is a slightly special case, because we already
> > > supported PV, simply by using a CPU model with the required feature
> > > (S390_FEAT_UNPACK).
> > >
> > > To integrate this with the option used by other platforms, we
> > > implement the following compromise:
> > >
> > > - When the confidential-guest-support option is set, s390 will
> > >recognize it, verify that the CPU can support PV (failing if not)
> > >and set virtio default options necessary for encrypted or protected
> > >guests, as on other platforms. i.e. if confidential-guest-support
> > >is set, we will either create a guest capable of entering PV mode,
> > >or fail outright.
> > >
> > > - If confidential-guest-support is not set, guests might still be
> > >able to enter PV mode, if the CPU has the right model. This may be
> > >a little surprising, but shouldn't actually be harmful.
> > >
> > > To start a guest supporting Protected Virtualization using the new
> > > option use the command line arguments:
> > > -object s390-pv-guest,id=pv0 -machine confidential-guest-support=pv0
> >
> >
> > This results in
> >
> > [cborntra@t35lp61 qemu]$ qemu-system-s390x -enable-kvm -nographic -m 2G
> > -kernel ~/full.normal
> > **
> > ERROR:../qom/object.c:317:type_initialize: assertion failed:
> > (parent->instance_size <= ti->instance_size)
> > Bail out! ERROR:../qom/object.c:317:type_initialize: assertion failed:
> > (parent->instance_size <= ti->instance_size)
> > Aborted (core dumped)
> >
>
> > > +static const TypeInfo s390_pv_guest_info = {
> > > +.parent = TYPE_CONFIDENTIAL_GUEST_SUPPORT,
> > > +.name = TYPE_S390_PV_GUEST,
> > > +.instance_size = sizeof(S390PVGuestState),
> > > +.interfaces = (InterfaceInfo[]) {
> > > +{ TYPE_USER_CREATABLE },
> > > +{ }
> > > +}
> > > +};
>
> I think this needs TYPE_OBJECT in .parent and
> TYPE_CONFIDENTIAL_GUEST_SUPPORT as an interface to fix the crash.
No, that was true of an earlier revision, but parent is correct in the
current version.
--
David Gibson| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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Re: [PATCH v6 13/13] s390: Recognize confidential-guest-support option
On Tue, Jan 12, 2021 at 12:36:07PM +0100, Cornelia Huck wrote:
> On Tue, 12 Jan 2021 09:15:26 +0100
> Christian Borntraeger wrote:
>
> > On 12.01.21 05:45, David Gibson wrote:
> > > At least some s390 cpu models support "Protected Virtualization" (PV),
> > > a mechanism to protect guests from eavesdropping by a compromised
> > > hypervisor.
> > >
> > > This is similar in function to other mechanisms like AMD's SEV and
> > > POWER's PEF, which are controlled by the "confidential-guest-support"
> > > machine option. s390 is a slightly special case, because we already
> > > supported PV, simply by using a CPU model with the required feature
> > > (S390_FEAT_UNPACK).
> > >
> > > To integrate this with the option used by other platforms, we
> > > implement the following compromise:
> > >
> > > - When the confidential-guest-support option is set, s390 will
> > >recognize it, verify that the CPU can support PV (failing if not)
> > >and set virtio default options necessary for encrypted or protected
> > >guests, as on other platforms. i.e. if confidential-guest-support
> > >is set, we will either create a guest capable of entering PV mode,
> > >or fail outright.
> > >
> > > - If confidential-guest-support is not set, guests might still be
> > >able to enter PV mode, if the CPU has the right model. This may be
> > >a little surprising, but shouldn't actually be harmful.
> > >
> > > To start a guest supporting Protected Virtualization using the new
> > > option use the command line arguments:
> > > -object s390-pv-guest,id=pv0 -machine confidential-guest-support=pv0
> >
> >
> > This results in
> >
> > [cborntra@t35lp61 qemu]$ qemu-system-s390x -enable-kvm -nographic -m 2G
> > -kernel ~/full.normal
> > **
> > ERROR:../qom/object.c:317:type_initialize: assertion failed:
> > (parent->instance_size <= ti->instance_size)
> > Bail out! ERROR:../qom/object.c:317:type_initialize: assertion failed:
> > (parent->instance_size <= ti->instance_size)
> > Aborted (core dumped)
> >
>
> > > +static const TypeInfo s390_pv_guest_info = {
> > > +.parent = TYPE_CONFIDENTIAL_GUEST_SUPPORT,
> > > +.name = TYPE_S390_PV_GUEST,
> > > +.instance_size = sizeof(S390PVGuestState),
> > > +.interfaces = (InterfaceInfo[]) {
> > > +{ TYPE_USER_CREATABLE },
> > > +{ }
> > > +}
> > > +};
>
> I think this needs TYPE_OBJECT in .parent and
> TYPE_CONFIDENTIAL_GUEST_SUPPORT as an interface to fix the crash.
Except TYPE_CONFIDENTIAL_GUEST_SUPPORT is declared as an object, not
an interface. Clearly something in this series is wrong though, as
the ppc impl uses it as if it were an interface.
Regards,
Daniel
--
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Re: [PATCH v6 13/13] s390: Recognize confidential-guest-support option
On 12.01.21 12:36, Cornelia Huck wrote:
> On Tue, 12 Jan 2021 09:15:26 +0100
> Christian Borntraeger wrote:
>
>> On 12.01.21 05:45, David Gibson wrote:
>>> At least some s390 cpu models support "Protected Virtualization" (PV),
>>> a mechanism to protect guests from eavesdropping by a compromised
>>> hypervisor.
>>>
>>> This is similar in function to other mechanisms like AMD's SEV and
>>> POWER's PEF, which are controlled by the "confidential-guest-support"
>>> machine option. s390 is a slightly special case, because we already
>>> supported PV, simply by using a CPU model with the required feature
>>> (S390_FEAT_UNPACK).
>>>
>>> To integrate this with the option used by other platforms, we
>>> implement the following compromise:
>>>
>>> - When the confidential-guest-support option is set, s390 will
>>>recognize it, verify that the CPU can support PV (failing if not)
>>>and set virtio default options necessary for encrypted or protected
>>>guests, as on other platforms. i.e. if confidential-guest-support
>>>is set, we will either create a guest capable of entering PV mode,
>>>or fail outright.
>>>
>>> - If confidential-guest-support is not set, guests might still be
>>>able to enter PV mode, if the CPU has the right model. This may be
>>>a little surprising, but shouldn't actually be harmful.
>>>
>>> To start a guest supporting Protected Virtualization using the new
>>> option use the command line arguments:
>>> -object s390-pv-guest,id=pv0 -machine confidential-guest-support=pv0
>>
>>
>> This results in
>>
>> [cborntra@t35lp61 qemu]$ qemu-system-s390x -enable-kvm -nographic -m 2G
>> -kernel ~/full.normal
>> **
>> ERROR:../qom/object.c:317:type_initialize: assertion failed:
>> (parent->instance_size <= ti->instance_size)
>> Bail out! ERROR:../qom/object.c:317:type_initialize: assertion failed:
>> (parent->instance_size <= ti->instance_size)
>> Aborted (core dumped)
>>
>
>>> +static const TypeInfo s390_pv_guest_info = {
>>> +.parent = TYPE_CONFIDENTIAL_GUEST_SUPPORT,
>>> +.name = TYPE_S390_PV_GUEST,
>>> +.instance_size = sizeof(S390PVGuestState),
>>> +.interfaces = (InterfaceInfo[]) {
>>> +{ TYPE_USER_CREATABLE },
>>> +{ }
>>> +}
>>> +};
>
> I think this needs TYPE_OBJECT in .parent and
> TYPE_CONFIDENTIAL_GUEST_SUPPORT as an interface to fix the crash.
It fixes the crash but it does not work:
qemu-system-s390x -enable-kvm -nographic -m 2G -kernel ~/image -object
s390-pv-guest,id=pv0 -machine confidential-guest-support=pv0
qemu-system-s390x: Invalid parameter type for 'confidential-guest-support',
expected: confidential-guest-support
Re: [PATCH v6 13/13] s390: Recognize confidential-guest-support option
On Tue, 12 Jan 2021 09:15:26 +0100
Christian Borntraeger wrote:
> On 12.01.21 05:45, David Gibson wrote:
> > At least some s390 cpu models support "Protected Virtualization" (PV),
> > a mechanism to protect guests from eavesdropping by a compromised
> > hypervisor.
> >
> > This is similar in function to other mechanisms like AMD's SEV and
> > POWER's PEF, which are controlled by the "confidential-guest-support"
> > machine option. s390 is a slightly special case, because we already
> > supported PV, simply by using a CPU model with the required feature
> > (S390_FEAT_UNPACK).
> >
> > To integrate this with the option used by other platforms, we
> > implement the following compromise:
> >
> > - When the confidential-guest-support option is set, s390 will
> >recognize it, verify that the CPU can support PV (failing if not)
> >and set virtio default options necessary for encrypted or protected
> >guests, as on other platforms. i.e. if confidential-guest-support
> >is set, we will either create a guest capable of entering PV mode,
> >or fail outright.
> >
> > - If confidential-guest-support is not set, guests might still be
> >able to enter PV mode, if the CPU has the right model. This may be
> >a little surprising, but shouldn't actually be harmful.
> >
> > To start a guest supporting Protected Virtualization using the new
> > option use the command line arguments:
> > -object s390-pv-guest,id=pv0 -machine confidential-guest-support=pv0
>
>
> This results in
>
> [cborntra@t35lp61 qemu]$ qemu-system-s390x -enable-kvm -nographic -m 2G
> -kernel ~/full.normal
> **
> ERROR:../qom/object.c:317:type_initialize: assertion failed:
> (parent->instance_size <= ti->instance_size)
> Bail out! ERROR:../qom/object.c:317:type_initialize: assertion failed:
> (parent->instance_size <= ti->instance_size)
> Aborted (core dumped)
>
> > +static const TypeInfo s390_pv_guest_info = {
> > +.parent = TYPE_CONFIDENTIAL_GUEST_SUPPORT,
> > +.name = TYPE_S390_PV_GUEST,
> > +.instance_size = sizeof(S390PVGuestState),
> > +.interfaces = (InterfaceInfo[]) {
> > +{ TYPE_USER_CREATABLE },
> > +{ }
> > +}
> > +};
I think this needs TYPE_OBJECT in .parent and
TYPE_CONFIDENTIAL_GUEST_SUPPORT as an interface to fix the crash.
Re: [PATCH v6 13/13] s390: Recognize confidential-guest-support option
On Tue, Jan 12, 2021 at 03:45:08PM +1100, David Gibson wrote:
> At least some s390 cpu models support "Protected Virtualization" (PV),
> a mechanism to protect guests from eavesdropping by a compromised
> hypervisor.
>
> This is similar in function to other mechanisms like AMD's SEV and
> POWER's PEF, which are controlled by the "confidential-guest-support"
> machine option. s390 is a slightly special case, because we already
> supported PV, simply by using a CPU model with the required feature
> (S390_FEAT_UNPACK).
>
> To integrate this with the option used by other platforms, we
> implement the following compromise:
>
> - When the confidential-guest-support option is set, s390 will
>recognize it, verify that the CPU can support PV (failing if not)
>and set virtio default options necessary for encrypted or protected
>guests, as on other platforms. i.e. if confidential-guest-support
>is set, we will either create a guest capable of entering PV mode,
>or fail outright.
>
> - If confidential-guest-support is not set, guests might still be
>able to enter PV mode, if the CPU has the right model. This may be
>a little surprising, but shouldn't actually be harmful.
>
> To start a guest supporting Protected Virtualization using the new
> option use the command line arguments:
> -object s390-pv-guest,id=pv0 -machine confidential-guest-support=pv0
>
> Signed-off-by: David Gibson
> ---
> docs/confidential-guest-support.txt | 3 ++
> docs/system/s390x/protvirt.rst | 19 +++---
> hw/s390x/pv.c | 58 +
> include/hw/s390x/pv.h | 1 +
> target/s390x/kvm.c | 3 ++
> 5 files changed, 78 insertions(+), 6 deletions(-)
> diff --git a/hw/s390x/pv.c b/hw/s390x/pv.c
> index ab3a2482aa..85592e100a 100644
> --- a/hw/s390x/pv.c
> +++ b/hw/s390x/pv.c
> @@ -14,8 +14,11 @@
> #include
>
> #include "cpu.h"
> +#include "qapi/error.h"
> #include "qemu/error-report.h"
> #include "sysemu/kvm.h"
> +#include "qom/object_interfaces.h"
> +#include "exec/confidential-guest-support.h"
> #include "hw/s390x/ipl.h"
> #include "hw/s390x/pv.h"
>
> @@ -111,3 +114,58 @@ void s390_pv_inject_reset_error(CPUState *cs)
> /* Report that we are unable to enter protected mode */
> env->regs[r1 + 1] = DIAG_308_RC_INVAL_FOR_PV;
> }
> +
> +#define TYPE_S390_PV_GUEST "s390-pv-guest"
> +#define S390_PV_GUEST(obj) \
> +OBJECT_CHECK(S390PVGuestState, (obj), TYPE_S390_PV_GUEST)
> +
> +typedef struct S390PVGuestState S390PVGuestState;
Can use OBJECT_DECLARE_TYPE for this. Also same comment about
struct naming vs type naming.
> +
> +/**
> + * S390PVGuestState:
> + *
> + * The S390PVGuestState object is basically a dummy used to tell the
> + * confidential guest support system to use s390's PV mechanism.
> + *
> + * # $QEMU \
> + * -object s390-pv-guest,id=pv0 \
> + * -machine ...,confidential-guest-support=pv0
> + */
> +struct S390PVGuestState {
> +Object parent_obj;
> +};
> +
> +int s390_pv_init(ConfidentialGuestSupport *cgs, Error **errp)
> +{
> +if (!object_dynamic_cast(OBJECT(cgs), TYPE_S390_PV_GUEST)) {
> +return 0;
> +}
> +
> +if (!s390_has_feat(S390_FEAT_UNPACK)) {
> +error_setg(errp,
> + "CPU model does not support Protected Virtualization");
> +return -1;
> +}
> +
> +cgs->ready = true;
> +
> +return 0;
> +}
> +
> +static const TypeInfo s390_pv_guest_info = {
> +.parent = TYPE_CONFIDENTIAL_GUEST_SUPPORT,
> +.name = TYPE_S390_PV_GUEST,
> +.instance_size = sizeof(S390PVGuestState),
> +.interfaces = (InterfaceInfo[]) {
> +{ TYPE_USER_CREATABLE },
> +{ }
> +}
> +};
> +
> +static void
> +s390_pv_register_types(void)
> +{
> +type_register_static(_pv_guest_info);
> +}
> +
> +type_init(s390_pv_register_types);
This can all use OBJECT_DEFINE_TYPE_WITH_INTERFACES
Regards,
Daniel
--
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Re: [PATCH v6 13/13] s390: Recognize confidential-guest-support option
On 12.01.21 05:45, David Gibson wrote: > At least some s390 cpu models support "Protected Virtualization" (PV), > a mechanism to protect guests from eavesdropping by a compromised > hypervisor. > > This is similar in function to other mechanisms like AMD's SEV and > POWER's PEF, which are controlled by the "confidential-guest-support" > machine option. s390 is a slightly special case, because we already > supported PV, simply by using a CPU model with the required feature > (S390_FEAT_UNPACK). > > To integrate this with the option used by other platforms, we > implement the following compromise: > > - When the confidential-guest-support option is set, s390 will >recognize it, verify that the CPU can support PV (failing if not) >and set virtio default options necessary for encrypted or protected >guests, as on other platforms. i.e. if confidential-guest-support >is set, we will either create a guest capable of entering PV mode, >or fail outright. > > - If confidential-guest-support is not set, guests might still be >able to enter PV mode, if the CPU has the right model. This may be >a little surprising, but shouldn't actually be harmful. > > To start a guest supporting Protected Virtualization using the new > option use the command line arguments: > -object s390-pv-guest,id=pv0 -machine confidential-guest-support=pv0 This results in [cborntra@t35lp61 qemu]$ qemu-system-s390x -enable-kvm -nographic -m 2G -kernel ~/full.normal ** ERROR:../qom/object.c:317:type_initialize: assertion failed: (parent->instance_size <= ti->instance_size) Bail out! ERROR:../qom/object.c:317:type_initialize: assertion failed: (parent->instance_size <= ti->instance_size) Aborted (core dumped) > > Signed-off-by: David Gibson > --- > docs/confidential-guest-support.txt | 3 ++ > docs/system/s390x/protvirt.rst | 19 +++--- > hw/s390x/pv.c | 58 + > include/hw/s390x/pv.h | 1 + > target/s390x/kvm.c | 3 ++ > 5 files changed, 78 insertions(+), 6 deletions(-) > > diff --git a/docs/confidential-guest-support.txt > b/docs/confidential-guest-support.txt > index d466aa79d5..b4912f66c2 100644 > --- a/docs/confidential-guest-support.txt > +++ b/docs/confidential-guest-support.txt > @@ -42,4 +42,7 @@ AMD Secure Encrypted Virtualization (SEV) > > POWER Protected Execution Facility (PEF) > > +s390x Protected Virtualization (PV) > +docs/system/s390x/protvirt.rst > + > Other mechanisms may be supported in future. > diff --git a/docs/system/s390x/protvirt.rst b/docs/system/s390x/protvirt.rst > index 712974ad87..0f481043d9 100644 > --- a/docs/system/s390x/protvirt.rst > +++ b/docs/system/s390x/protvirt.rst > @@ -22,15 +22,22 @@ If those requirements are met, the capability > `KVM_CAP_S390_PROTECTED` > will indicate that KVM can support PVMs on that LPAR. > > > -QEMU Settings > -- > +Running a Protected Virtual Machine > +--- > > -To indicate to the VM that it can transition into protected mode, the > +To run a PVM you will need to select a CPU model which includes the > `Unpack facility` (stfle bit 161 represented by the feature > -`unpack`/`S390_FEAT_UNPACK`) needs to be part of the cpu model of > -the VM. > +`unpack`/`S390_FEAT_UNPACK`), and add these options to the command line:: > + > +-object s390-pv-guest,id=pv0 \ > +-machine confidential-guest-support=pv0 > + > +Adding these options will: > + > +* Ensure the `unpack` facility is available > +* Enable the IOMMU by default for all I/O devices > +* Initialize the PV mechanism > > -All I/O devices need to use the IOMMU. > Passthrough (vfio) devices are currently not supported. > > Host huge page backings are not supported. However guests can use huge > diff --git a/hw/s390x/pv.c b/hw/s390x/pv.c > index ab3a2482aa..85592e100a 100644 > --- a/hw/s390x/pv.c > +++ b/hw/s390x/pv.c > @@ -14,8 +14,11 @@ > #include > > #include "cpu.h" > +#include "qapi/error.h" > #include "qemu/error-report.h" > #include "sysemu/kvm.h" > +#include "qom/object_interfaces.h" > +#include "exec/confidential-guest-support.h" > #include "hw/s390x/ipl.h" > #include "hw/s390x/pv.h" > > @@ -111,3 +114,58 @@ void s390_pv_inject_reset_error(CPUState *cs) > /* Report that we are unable to enter protected mode */ > env->regs[r1 + 1] = DIAG_308_RC_INVAL_FOR_PV; > } > + > +#define TYPE_S390_PV_GUEST "s390-pv-guest" > +#define S390_PV_GUEST(obj) \ > +OBJECT_CHECK(S390PVGuestState, (obj), TYPE_S390_PV_GUEST) > + > +typedef struct S390PVGuestState S390PVGuestState; > + > +/** > + * S390PVGuestState: > + * > + * The S390PVGuestState object is basically a dummy used to tell the > + * confidential guest support system to use s390's PV mechanism. > + * > + * # $QEMU \ > + * -object s390-pv-guest,id=pv0 \ > + * -machine
[PATCH v6 13/13] s390: Recognize confidential-guest-support option
At least some s390 cpu models support "Protected Virtualization" (PV),
a mechanism to protect guests from eavesdropping by a compromised
hypervisor.
This is similar in function to other mechanisms like AMD's SEV and
POWER's PEF, which are controlled by the "confidential-guest-support"
machine option. s390 is a slightly special case, because we already
supported PV, simply by using a CPU model with the required feature
(S390_FEAT_UNPACK).
To integrate this with the option used by other platforms, we
implement the following compromise:
- When the confidential-guest-support option is set, s390 will
recognize it, verify that the CPU can support PV (failing if not)
and set virtio default options necessary for encrypted or protected
guests, as on other platforms. i.e. if confidential-guest-support
is set, we will either create a guest capable of entering PV mode,
or fail outright.
- If confidential-guest-support is not set, guests might still be
able to enter PV mode, if the CPU has the right model. This may be
a little surprising, but shouldn't actually be harmful.
To start a guest supporting Protected Virtualization using the new
option use the command line arguments:
-object s390-pv-guest,id=pv0 -machine confidential-guest-support=pv0
Signed-off-by: David Gibson
---
docs/confidential-guest-support.txt | 3 ++
docs/system/s390x/protvirt.rst | 19 +++---
hw/s390x/pv.c | 58 +
include/hw/s390x/pv.h | 1 +
target/s390x/kvm.c | 3 ++
5 files changed, 78 insertions(+), 6 deletions(-)
diff --git a/docs/confidential-guest-support.txt
b/docs/confidential-guest-support.txt
index d466aa79d5..b4912f66c2 100644
--- a/docs/confidential-guest-support.txt
+++ b/docs/confidential-guest-support.txt
@@ -42,4 +42,7 @@ AMD Secure Encrypted Virtualization (SEV)
POWER Protected Execution Facility (PEF)
+s390x Protected Virtualization (PV)
+docs/system/s390x/protvirt.rst
+
Other mechanisms may be supported in future.
diff --git a/docs/system/s390x/protvirt.rst b/docs/system/s390x/protvirt.rst
index 712974ad87..0f481043d9 100644
--- a/docs/system/s390x/protvirt.rst
+++ b/docs/system/s390x/protvirt.rst
@@ -22,15 +22,22 @@ If those requirements are met, the capability
`KVM_CAP_S390_PROTECTED`
will indicate that KVM can support PVMs on that LPAR.
-QEMU Settings
--
+Running a Protected Virtual Machine
+---
-To indicate to the VM that it can transition into protected mode, the
+To run a PVM you will need to select a CPU model which includes the
`Unpack facility` (stfle bit 161 represented by the feature
-`unpack`/`S390_FEAT_UNPACK`) needs to be part of the cpu model of
-the VM.
+`unpack`/`S390_FEAT_UNPACK`), and add these options to the command line::
+
+-object s390-pv-guest,id=pv0 \
+-machine confidential-guest-support=pv0
+
+Adding these options will:
+
+* Ensure the `unpack` facility is available
+* Enable the IOMMU by default for all I/O devices
+* Initialize the PV mechanism
-All I/O devices need to use the IOMMU.
Passthrough (vfio) devices are currently not supported.
Host huge page backings are not supported. However guests can use huge
diff --git a/hw/s390x/pv.c b/hw/s390x/pv.c
index ab3a2482aa..85592e100a 100644
--- a/hw/s390x/pv.c
+++ b/hw/s390x/pv.c
@@ -14,8 +14,11 @@
#include
#include "cpu.h"
+#include "qapi/error.h"
#include "qemu/error-report.h"
#include "sysemu/kvm.h"
+#include "qom/object_interfaces.h"
+#include "exec/confidential-guest-support.h"
#include "hw/s390x/ipl.h"
#include "hw/s390x/pv.h"
@@ -111,3 +114,58 @@ void s390_pv_inject_reset_error(CPUState *cs)
/* Report that we are unable to enter protected mode */
env->regs[r1 + 1] = DIAG_308_RC_INVAL_FOR_PV;
}
+
+#define TYPE_S390_PV_GUEST "s390-pv-guest"
+#define S390_PV_GUEST(obj) \
+OBJECT_CHECK(S390PVGuestState, (obj), TYPE_S390_PV_GUEST)
+
+typedef struct S390PVGuestState S390PVGuestState;
+
+/**
+ * S390PVGuestState:
+ *
+ * The S390PVGuestState object is basically a dummy used to tell the
+ * confidential guest support system to use s390's PV mechanism.
+ *
+ * # $QEMU \
+ * -object s390-pv-guest,id=pv0 \
+ * -machine ...,confidential-guest-support=pv0
+ */
+struct S390PVGuestState {
+Object parent_obj;
+};
+
+int s390_pv_init(ConfidentialGuestSupport *cgs, Error **errp)
+{
+if (!object_dynamic_cast(OBJECT(cgs), TYPE_S390_PV_GUEST)) {
+return 0;
+}
+
+if (!s390_has_feat(S390_FEAT_UNPACK)) {
+error_setg(errp,
+ "CPU model does not support Protected Virtualization");
+return -1;
+}
+
+cgs->ready = true;
+
+return 0;
+}
+
+static const TypeInfo s390_pv_guest_info = {
+.parent = TYPE_CONFIDENTIAL_GUEST_SUPPORT,
+.name = TYPE_S390_PV_GUEST,
+.instance_size = sizeof(S390PVGuestState),
+.interfaces =
