| Message ID | 1368942460-15577-11-git-send-email-sanjayl@kymasys.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Il 19/05/2013 07:47, Sanjay Lal ha scritto: > - Add API to allow clients (QEMU etc.) to check whether the H/W > supports the MIPS VZ-ASE. Why does this matter to userspace? Do the userspace have some way to detect if the kernel is unmodified or minimally-modified? Paolo > Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> > --- > include/uapi/linux/kvm.h | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index a5c86fc..5889e976 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -666,6 +666,7 @@ struct kvm_ppc_smmu_info { > #define KVM_CAP_IRQ_MPIC 90 > #define KVM_CAP_PPC_RTAS 91 > #define KVM_CAP_IRQ_XICS 92 > +#define KVM_CAP_MIPS_VZ_ASE 93 > > #ifdef KVM_CAP_IRQ_ROUTING > > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 05/28/2013 09:34 AM, Paolo Bonzini wrote: > Il 19/05/2013 07:47, Sanjay Lal ha scritto: >> - Add API to allow clients (QEMU etc.) to check whether the H/W >> supports the MIPS VZ-ASE. > > Why does this matter to userspace? Do the userspace have some way to > detect if the kernel is unmodified or minimally-modified? > There are (will be) two types of VM presented by MIPS KVM: 1) That provided by the initial patch where a faux-MIPS is emulated and all kernel code must be in the USEG address space. 2) Real MIPS, addressing works as per the architecture specification. Presumably the user-space client would like to know which of these are supported, as well as be able to select the desired model. I don't know the best way to do this, but I agree that KVM_CAP_MIPS_VZ_ASE is probably not the best name for it. My idea was to have the arg of the KVM_CREATE_VM ioctl specify the desired style David Daney > Paolo > >> Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> >> --- >> include/uapi/linux/kvm.h | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h >> index a5c86fc..5889e976 100644 >> --- a/include/uapi/linux/kvm.h >> +++ b/include/uapi/linux/kvm.h >> @@ -666,6 +666,7 @@ struct kvm_ppc_smmu_info { >> #define KVM_CAP_IRQ_MPIC 90 >> #define KVM_CAP_PPC_RTAS 91 >> #define KVM_CAP_IRQ_XICS 92 >> +#define KVM_CAP_MIPS_VZ_ASE 93 >> >> #ifdef KVM_CAP_IRQ_ROUTING >> >> > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Il 30/05/2013 19:07, David Daney ha scritto: > On 05/28/2013 09:34 AM, Paolo Bonzini wrote: >> Il 19/05/2013 07:47, Sanjay Lal ha scritto: >>> - Add API to allow clients (QEMU etc.) to check whether the H/W >>> supports the MIPS VZ-ASE. >> >> Why does this matter to userspace? Do the userspace have some way to >> detect if the kernel is unmodified or minimally-modified? >> > > There are (will be) two types of VM presented by MIPS KVM: > > 1) That provided by the initial patch where a faux-MIPS is emulated and > all kernel code must be in the USEG address space. > > 2) Real MIPS, addressing works as per the architecture specification. > > Presumably the user-space client would like to know which of these are > supported, as well as be able to select the desired model. Understood. It's really two different machine types. > I don't know the best way to do this, but I agree that > KVM_CAP_MIPS_VZ_ASE is probably not the best name for it. > > My idea was to have the arg of the KVM_CREATE_VM ioctl specify the > desired style Ok. How complex is it? Do you plan to do this when the patches are "really ready" for Linus' tree? Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On May 30, 2013, at 10:07 AM, David Daney wrote: > On 05/28/2013 09:34 AM, Paolo Bonzini wrote: >> Il 19/05/2013 07:47, Sanjay Lal ha scritto: >>> - Add API to allow clients (QEMU etc.) to check whether the H/W >>> supports the MIPS VZ-ASE. >> >> Why does this matter to userspace? Do the userspace have some way to >> detect if the kernel is unmodified or minimally-modified? >> > > There are (will be) two types of VM presented by MIPS KVM: > > 1) That provided by the initial patch where a faux-MIPS is emulated and all kernel code must be in the USEG address space. > > 2) Real MIPS, addressing works as per the architecture specification. > > Presumably the user-space client would like to know which of these are supported, as well as be able to select the desired model. > > I don't know the best way to do this, but I agree that KVM_CAP_MIPS_VZ_ASE is probably not the best name for it. > > My idea was to have the arg of the KVM_CREATE_VM ioctl specify the desired style > > David Daney > > Hi Paolo, just wanted to add to David's comments. KVM/MIPS currently supports the two modes David mentioned, based on a kernel config option. KVM_CAP_MIPS_VZ_ASE is used by QEMU to make sure that the kvm module currently loaded supports the H/W virtualization. Its a bit cumbersome on MIPS, because you really can't fall back to trap and emulate, since the guest kernel for trap and emulate has a user mode link address. I am open to other ways of doing this. Regards Sanjay -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 05/30/2013 10:51 AM, Paolo Bonzini wrote: > Il 30/05/2013 19:07, David Daney ha scritto: >> On 05/28/2013 09:34 AM, Paolo Bonzini wrote: >>> Il 19/05/2013 07:47, Sanjay Lal ha scritto: >>>> - Add API to allow clients (QEMU etc.) to check whether the H/W >>>> supports the MIPS VZ-ASE. >>> >>> Why does this matter to userspace? Do the userspace have some way to >>> detect if the kernel is unmodified or minimally-modified? >>> >> >> There are (will be) two types of VM presented by MIPS KVM: >> >> 1) That provided by the initial patch where a faux-MIPS is emulated and >> all kernel code must be in the USEG address space. >> >> 2) Real MIPS, addressing works as per the architecture specification. >> >> Presumably the user-space client would like to know which of these are >> supported, as well as be able to select the desired model. > > Understood. It's really two different machine types. > >> I don't know the best way to do this, but I agree that >> KVM_CAP_MIPS_VZ_ASE is probably not the best name for it. >> >> My idea was to have the arg of the KVM_CREATE_VM ioctl specify the >> desired style > > Ok. How complex is it? Do you plan to do this when the patches are > "really ready" for Linus' tree? I am currently working on preparing a patch set that implements MIPS-VZ in a slightly different manner than Sanjay's patches. So there will likely be some back and forth getting everything properly integrated into a sane implementation So I don't know exactly how to answer this question other than to say, that I don't think things should go into Linus's tree until they are "really ready", which would include resolving this issue. David Daney -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index a5c86fc..5889e976 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -666,6 +666,7 @@ struct kvm_ppc_smmu_info { #define KVM_CAP_IRQ_MPIC 90 #define KVM_CAP_PPC_RTAS 91 #define KVM_CAP_IRQ_XICS 92 +#define KVM_CAP_MIPS_VZ_ASE 93 #ifdef KVM_CAP_IRQ_ROUTING
- Add API to allow clients (QEMU etc.) to check whether the H/W supports the MIPS VZ-ASE. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> --- include/uapi/linux/kvm.h | 1 + 1 file changed, 1 insertion(+)