| Message ID | 20250124151732.6072-4-shameerali.kolothum.thodi@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | KVM: arm64: Errata management for VM Live migration | expand |
On Fri, Jan 24 2025, Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> wrote: > Currently ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID returns the > bitmap corresponding to KVM_REG_ARM_VENDOR_HYP_BMAP and it only > returns _KVM_FEATURES_FUNC_ID and _KVM_PTP_FUNC_ID. Change that > to return all the KVM/arm64-specific hypercalls exposed by > KVM/arm64 to guest operating systems. > > Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> > --- > arch/arm64/kvm/hypercalls.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c > index 27ce4cb44904..6132cb542200 100644 > --- a/arch/arm64/kvm/hypercalls.c > +++ b/arch/arm64/kvm/hypercalls.c > @@ -359,7 +359,11 @@ int kvm_smccc_call_handler(struct kvm_vcpu *vcpu) > val[3] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3; > break; > case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID: > - val[0] = smccc_feat->vendor_hyp_bmap; > + val[0] = GENMASK(ARM_SMCCC_KVM_FUNC_MMIO_GUARD, > + ARM_SMCCC_KVM_FUNC_FEATURES); Don't you need to exclude the reserved ids 5 and 6? > + /* Function numbers 8-63 are reserved for pKVM for now */ > + val[2] = GENMASK((ARM_SMCCC_KVM_FUNC_DISCOVER_IMPL_CPUS - 64), > + (ARM_SMCCC_KVM_FUNC_DISCOVER_IMPL_VER - 64)); > break; > case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID: > kvm_ptp_get_time(vcpu, val);
> -----Original Message----- > From: Cornelia Huck <cohuck@redhat.com> > Sent: Monday, January 27, 2025 12:47 PM > To: Shameerali Kolothum Thodi > <shameerali.kolothum.thodi@huawei.com>; kvmarm@lists.linux.dev; > maz@kernel.org; oliver.upton@linux.dev > Cc: catalin.marinas@arm.com; will@kernel.org; mark.rutland@arm.com; > eric.auger@redhat.com; sebott@redhat.com; yuzenghui > <yuzenghui@huawei.com>; Wangzhou (B) <wangzhou1@hisilicon.com>; > jiangkunkun <jiangkunkun@huawei.com>; Jonathan Cameron > <jonathan.cameron@huawei.com>; Anthony Jebson > <anthony.jebson@huawei.com>; linux-arm-kernel@lists.infradead.org; > Linuxarm <linuxarm@huawei.com> > Subject: Re: [PATCH v5 3/4] KVM: arm64: Report all the KVM/arm64-specific > hypercalls > > On Fri, Jan 24 2025, Shameer Kolothum > <shameerali.kolothum.thodi@huawei.com> wrote: > > > Currently ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID returns > the > > bitmap corresponding to KVM_REG_ARM_VENDOR_HYP_BMAP and it > only > > returns _KVM_FEATURES_FUNC_ID and _KVM_PTP_FUNC_ID. Change that > > to return all the KVM/arm64-specific hypercalls exposed by > > KVM/arm64 to guest operating systems. > > > > Signed-off-by: Shameer Kolothum > <shameerali.kolothum.thodi@huawei.com> > > --- > > arch/arm64/kvm/hypercalls.c | 6 +++++- > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c > > index 27ce4cb44904..6132cb542200 100644 > > --- a/arch/arm64/kvm/hypercalls.c > > +++ b/arch/arm64/kvm/hypercalls.c > > @@ -359,7 +359,11 @@ int kvm_smccc_call_handler(struct kvm_vcpu > *vcpu) > > val[3] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3; > > break; > > case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID: > > - val[0] = smccc_feat->vendor_hyp_bmap; > > + val[0] = GENMASK(ARM_SMCCC_KVM_FUNC_MMIO_GUARD, > > + ARM_SMCCC_KVM_FUNC_FEATURES); > > Don't you need to exclude the reserved ids 5 and 6? Oops...I overlooked it. Will correct. Thanks, Shameer
Hi Shameer, On Fri, Jan 24, 2025 at 03:17:31PM +0000, Shameer Kolothum wrote: > Currently ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID returns the > bitmap corresponding to KVM_REG_ARM_VENDOR_HYP_BMAP and it only > returns _KVM_FEATURES_FUNC_ID and _KVM_PTP_FUNC_ID. Change that > to return all the KVM/arm64-specific hypercalls exposed by > KVM/arm64 to guest operating systems. > > Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> > --- > arch/arm64/kvm/hypercalls.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c > index 27ce4cb44904..6132cb542200 100644 > --- a/arch/arm64/kvm/hypercalls.c > +++ b/arch/arm64/kvm/hypercalls.c > @@ -359,7 +359,11 @@ int kvm_smccc_call_handler(struct kvm_vcpu *vcpu) > val[3] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3; > break; > case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID: > - val[0] = smccc_feat->vendor_hyp_bmap; > + val[0] = GENMASK(ARM_SMCCC_KVM_FUNC_MMIO_GUARD, > + ARM_SMCCC_KVM_FUNC_FEATURES); > + /* Function numbers 8-63 are reserved for pKVM for now */ > + val[2] = GENMASK((ARM_SMCCC_KVM_FUNC_DISCOVER_IMPL_CPUS - 64), > + (ARM_SMCCC_KVM_FUNC_DISCOVER_IMPL_VER - 64)); > break; This isn't right. The pKVM carveout exists for some KVM-internal bookkeeping to (hopefully) avoid breaking guest ABI between what's in the downstream android kernel and what eventually gets accepted upstream. The purpose of this hypercall is for the guest to discover what interfaces are actually implemented by the hypervisor, and we definitely do not implement these upstream at the moment.
> -----Original Message----- > From: Oliver Upton <oliver.upton@linux.dev> > Sent: Monday, January 27, 2025 5:06 PM > To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com> > Cc: kvmarm@lists.linux.dev; maz@kernel.org; catalin.marinas@arm.com; > will@kernel.org; mark.rutland@arm.com; cohuck@redhat.com; > eric.auger@redhat.com; sebott@redhat.com; yuzenghui > <yuzenghui@huawei.com>; Wangzhou (B) <wangzhou1@hisilicon.com>; > jiangkunkun <jiangkunkun@huawei.com>; Jonathan Cameron > <jonathan.cameron@huawei.com>; Anthony Jebson > <anthony.jebson@huawei.com>; linux-arm-kernel@lists.infradead.org; > Linuxarm <linuxarm@huawei.com> > Subject: Re: [PATCH v5 3/4] KVM: arm64: Report all the KVM/arm64-specific > hypercalls > > Hi Shameer, > > On Fri, Jan 24, 2025 at 03:17:31PM +0000, Shameer Kolothum wrote: > > Currently ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID returns > the bitmap > > corresponding to KVM_REG_ARM_VENDOR_HYP_BMAP and it only > returns > > _KVM_FEATURES_FUNC_ID and _KVM_PTP_FUNC_ID. Change that to > return all > > the KVM/arm64-specific hypercalls exposed by > > KVM/arm64 to guest operating systems. > > > > Signed-off-by: Shameer Kolothum > <shameerali.kolothum.thodi@huawei.com> > > --- > > arch/arm64/kvm/hypercalls.c | 6 +++++- > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c > > index 27ce4cb44904..6132cb542200 100644 > > --- a/arch/arm64/kvm/hypercalls.c > > +++ b/arch/arm64/kvm/hypercalls.c > > @@ -359,7 +359,11 @@ int kvm_smccc_call_handler(struct kvm_vcpu > *vcpu) > > val[3] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3; > > break; > > case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID: > > - val[0] = smccc_feat->vendor_hyp_bmap; > > + val[0] = GENMASK(ARM_SMCCC_KVM_FUNC_MMIO_GUARD, > > + ARM_SMCCC_KVM_FUNC_FEATURES); > > + /* Function numbers 8-63 are reserved for pKVM for now */ > > + val[2] = > GENMASK((ARM_SMCCC_KVM_FUNC_DISCOVER_IMPL_CPUS - 64), > > + > (ARM_SMCCC_KVM_FUNC_DISCOVER_IMPL_VER - 64)); > > break; > > This isn't right. The pKVM carveout exists for some KVM-internal > bookkeeping to (hopefully) avoid breaking guest ABI between what's in the > downstream android kernel and what eventually gets accepted upstream. > > The purpose of this hypercall is for the guest to discover what interfaces are > actually implemented by the hypervisor, and we definitely do not > implement these upstream at the moment. Ok. I had some confusion on pKVM ones as I could see the kvm_arm_hyp_service_available() being called with those in arm-pkvm-guest.c. So that explains it. . I will remove the pKVM ones and just add support to report the ones introduced in this series. Thanks, Shameer
diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c index 27ce4cb44904..6132cb542200 100644 --- a/arch/arm64/kvm/hypercalls.c +++ b/arch/arm64/kvm/hypercalls.c @@ -359,7 +359,11 @@ int kvm_smccc_call_handler(struct kvm_vcpu *vcpu) val[3] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3; break; case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID: - val[0] = smccc_feat->vendor_hyp_bmap; + val[0] = GENMASK(ARM_SMCCC_KVM_FUNC_MMIO_GUARD, + ARM_SMCCC_KVM_FUNC_FEATURES); + /* Function numbers 8-63 are reserved for pKVM for now */ + val[2] = GENMASK((ARM_SMCCC_KVM_FUNC_DISCOVER_IMPL_CPUS - 64), + (ARM_SMCCC_KVM_FUNC_DISCOVER_IMPL_VER - 64)); break; case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID: kvm_ptp_get_time(vcpu, val);
Currently ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID returns the bitmap corresponding to KVM_REG_ARM_VENDOR_HYP_BMAP and it only returns _KVM_FEATURES_FUNC_ID and _KVM_PTP_FUNC_ID. Change that to return all the KVM/arm64-specific hypercalls exposed by KVM/arm64 to guest operating systems. Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> --- arch/arm64/kvm/hypercalls.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)