It will be very useful for user space (QEMU/KVMTOOL) if it has a method of querying VCPU target type matching to underlying Host. We can use such querying mechanism and implement machine models in user space where VCPU target type is always same-as/similar-to underlying Host (i.e. Target CPU=Host).
This patch series implements KVM_ARM_PREFERRED_TARGET vm ioclt for querying VCPU target type matching underlying host. Using this new ioctl we can implement VCPU target CPU=Host in user space.
Also, it is not mandatory to call KVM_ARM_PREFERRED_TARGET vm ioctl and the old method of trying all possible target types using the KVM_ARM_VCPU_INIT ioctl to initialize VCPU works fine.
V5: - Update documentation based on review comments
V4: - Fixed files exchanged between patches - For now return zeroed features in struct kvm_vcpu_init instance
V3: - Return -ENODEV if no preferred target available for host - Make KVM_ARM_PREFERRED_TARGET ioctl as vm ioctl
V2: - Renamed the ioclt to KVM_ARM_PREFERRED_TARGET - Return struct kvm_vcpu_init instace instead of just target type
V1: - Initial patch-set with ioctl named as KVM_ARM_SUITABLE_TARGET
Anup Patel (4): ARM: KVM: Implement kvm_vcpu_preferred_target() function ARM64: KVM: Implement kvm_vcpu_preferred_target() function ARM/ARM64: KVM: Implement KVM_ARM_PREFERRED_TARGET ioctl KVM: Add documentation for KVM_ARM_PREFERRED_TARGET ioctl
Documentation/virtual/kvm/api.txt | 31 +++++++++++++++++++++++++++---- arch/arm/include/asm/kvm_host.h | 1 + arch/arm/kvm/arm.c | 13 +++++++++++++ arch/arm/kvm/guest.c | 20 ++++++++++++++++++++ arch/arm64/include/asm/kvm_host.h | 1 + arch/arm64/kvm/guest.c | 20 ++++++++++++++++++++ include/uapi/linux/kvm.h | 1 + 7 files changed, 83 insertions(+), 4 deletions(-)
This patch implements kvm_vcpu_preferred_target() function for KVM ARM which will help us implement KVM_ARM_PREFERRED_TARGET ioctl for user space.
Signed-off-by: Anup Patel anup.patel@linaro.org Signed-off-by: Pranavkumar Sawargaonkar pranavkumar@linaro.org --- arch/arm/include/asm/kvm_host.h | 1 + arch/arm/kvm/guest.c | 20 ++++++++++++++++++++ 2 files changed, 21 insertions(+)
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index 7d22517..76f3c19 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -154,6 +154,7 @@ struct kvm_vcpu_stat { struct kvm_vcpu_init; int kvm_vcpu_set_target(struct kvm_vcpu *vcpu, const struct kvm_vcpu_init *init); +int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init); unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu); int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *indices); struct kvm_one_reg; diff --git a/arch/arm/kvm/guest.c b/arch/arm/kvm/guest.c index 152d036..21beea0 100644 --- a/arch/arm/kvm/guest.c +++ b/arch/arm/kvm/guest.c @@ -222,6 +222,26 @@ int kvm_vcpu_set_target(struct kvm_vcpu *vcpu, return kvm_reset_vcpu(vcpu); }
+int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init) +{ + int target = kvm_target_cpu(); + + if (target < 0) + return -ENODEV; + + memset(init, 0, sizeof(*init)); + + /* + * For now, we don't return any features. + * In future, we might use features to return target + * specific features available for the preferred + * target type. + */ + init->target = (__u32)target; + + return 0; +} + int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu) { return -EINVAL;
This patch implements kvm_vcpu_preferred_target() function for KVM ARM64 which will help us implement KVM_ARM_PREFERRED_TARGET ioctl for user space.
Signed-off-by: Anup Patel anup.patel@linaro.org Signed-off-by: Pranavkumar Sawargaonkar pranavkumar@linaro.org --- arch/arm64/include/asm/kvm_host.h | 1 + arch/arm64/kvm/guest.c | 20 ++++++++++++++++++++ 2 files changed, 21 insertions(+)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index f318c43..b609db3 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -156,6 +156,7 @@ struct kvm_vcpu_stat { struct kvm_vcpu_init; int kvm_vcpu_set_target(struct kvm_vcpu *vcpu, const struct kvm_vcpu_init *init); +int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init); unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu); int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *indices); struct kvm_one_reg; diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index d7bf7d6..94e4b7a 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -254,6 +254,26 @@ int kvm_vcpu_set_target(struct kvm_vcpu *vcpu, return kvm_reset_vcpu(vcpu); }
+int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init) +{ + int target = kvm_target_cpu(); + + if (target < 0) + return -ENODEV; + + memset(init, 0, sizeof(*init)); + + /* + * For now, we don't return any features. + * In future, we might use features to return target + * specific features available for the preferred + * target type. + */ + init->target = (__u32)target; + + return 0; +} + int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu) { return -EINVAL;
For implementing CPU=host, we need a mechanism for querying preferred VCPU target type on underlying Host.
This patch implements KVM_ARM_PREFERRED_TARGET vm ioctl which returns struct kvm_vcpu_init instance containing information about preferred VCPU target type and target specific features available for it.
Signed-off-by: Anup Patel anup.patel@linaro.org Signed-off-by: Pranavkumar Sawargaonkar pranavkumar@linaro.org --- arch/arm/kvm/arm.c | 13 +++++++++++++ include/uapi/linux/kvm.h | 1 + 2 files changed, 14 insertions(+)
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 9c697db..cc5adb9 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -797,6 +797,19 @@ long kvm_arch_vm_ioctl(struct file *filp, return -EFAULT; return kvm_vm_ioctl_set_device_addr(kvm, &dev_addr); } + case KVM_ARM_PREFERRED_TARGET: { + int err; + struct kvm_vcpu_init init; + + err = kvm_vcpu_preferred_target(&init); + if (err) + return err; + + if (copy_to_user(argp, &init, sizeof(init))) + return -EFAULT; + + return 0; + } default: return -EINVAL; } diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 99c2533..e32e776 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1012,6 +1012,7 @@ struct kvm_s390_ucas_mapping { /* VM is being stopped by host */ #define KVM_KVMCLOCK_CTRL _IO(KVMIO, 0xad) #define KVM_ARM_VCPU_INIT _IOW(KVMIO, 0xae, struct kvm_vcpu_init) +#define KVM_ARM_PREFERRED_TARGET _IOR(KVMIO, 0xaf, struct kvm_vcpu_init) #define KVM_GET_REG_LIST _IOWR(KVMIO, 0xb0, struct kvm_reg_list)
#define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0)
To implement CPU=Host we have added KVM_ARM_PREFERRED_TARGET vm ioctl which provides information to user space required for creating VCPU matching underlying Host.
This patch adds info related to this new KVM_ARM_PREFERRED_TARGET vm ioctl in the KVM API documentation.
Signed-off-by: Anup Patel anup.patel@linaro.org Signed-off-by: Pranavkumar Sawargaonkar pranavkumar@linaro.org --- Documentation/virtual/kvm/api.txt | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 858aecf..076b849 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -2304,7 +2304,31 @@ Possible features: Depends on KVM_CAP_ARM_EL1_32BIT (arm64 only).
-4.83 KVM_GET_REG_LIST +4.83 KVM_ARM_PREFERRED_TARGET + +Capability: basic +Architectures: arm, arm64 +Type: vm ioctl +Parameters: struct struct kvm_vcpu_init (out) +Returns: 0 on success; -1 on error +Errors: + ENODEV: no preferred target available for the host + +This queries KVM for preferred CPU target type which can be emulated +by KVM on underlying host. + +The ioctl returns struct kvm_vcpu_init instance containing information +about preferred CPU target type and recommended features for it. The +kvm_vcpu_init->features bitmap returned will have feature bits set if +the preferred target recommends setting these features, but this is +not mandatory. + +The information returned by this ioctl can be used to prepare an instance +of struct kvm_vcpu_init for KVM_ARM_VCPU_INIT ioctl which will result in +in VCPU matching underlying host. + + +4.84 KVM_GET_REG_LIST
Capability: basic Architectures: arm, arm64 @@ -2323,8 +2347,7 @@ struct kvm_reg_list { This ioctl returns the guest registers that are supported for the KVM_GET_ONE_REG/KVM_SET_ONE_REG calls.
- -4.84 KVM_ARM_SET_DEVICE_ADDR +4.85 KVM_ARM_SET_DEVICE_ADDR
Capability: KVM_CAP_ARM_SET_DEVICE_ADDR Architectures: arm, arm64 @@ -2362,7 +2385,7 @@ must be called after calling KVM_CREATE_IRQCHIP, but before calling KVM_RUN on any of the VCPUs. Calling this ioctl twice for any of the base addresses will return -EEXIST.
-4.85 KVM_PPC_RTAS_DEFINE_TOKEN +4.86 KVM_PPC_RTAS_DEFINE_TOKEN
Capability: KVM_CAP_PPC_RTAS Architectures: ppc
On Mon, Sep 30, 2013 at 02:20:04PM +0530, Anup Patel wrote:
It will be very useful for user space (QEMU/KVMTOOL) if it has a method of querying VCPU target type matching to underlying Host. We can use such querying mechanism and implement machine models in user space where VCPU target type is always same-as/similar-to underlying Host (i.e. Target CPU=Host).
This patch series implements KVM_ARM_PREFERRED_TARGET vm ioclt for querying VCPU target type matching underlying host. Using this new ioctl we can implement VCPU target CPU=Host in user space.
Also, it is not mandatory to call KVM_ARM_PREFERRED_TARGET vm ioctl and the old method of trying all possible target types using the KVM_ARM_VCPU_INIT ioctl to initialize VCPU works fine.
Looks good to me, as soon as Marc acks this one, I'll merge it.
-Christoffer
On 02/10/13 17:04, Christoffer Dall wrote:
On Mon, Sep 30, 2013 at 02:20:04PM +0530, Anup Patel wrote:
It will be very useful for user space (QEMU/KVMTOOL) if it has a method of querying VCPU target type matching to underlying Host. We can use such querying mechanism and implement machine models in user space where VCPU target type is always same-as/similar-to underlying Host (i.e. Target CPU=Host).
This patch series implements KVM_ARM_PREFERRED_TARGET vm ioclt for querying VCPU target type matching underlying host. Using this new ioctl we can implement VCPU target CPU=Host in user space.
Also, it is not mandatory to call KVM_ARM_PREFERRED_TARGET vm ioctl and the old method of trying all possible target types using the KVM_ARM_VCPU_INIT ioctl to initialize VCPU works fine.
Looks good to me, as soon as Marc acks this one, I'll merge it.
Yup, go for it:
Acked-by: Marc Zyngier marc.zyngier@arm.com
M.
On Wed, Oct 02, 2013 at 05:17:41PM +0100, Marc Zyngier wrote:
On 02/10/13 17:04, Christoffer Dall wrote:
On Mon, Sep 30, 2013 at 02:20:04PM +0530, Anup Patel wrote:
It will be very useful for user space (QEMU/KVMTOOL) if it has a method of querying VCPU target type matching to underlying Host. We can use such querying mechanism and implement machine models in user space where VCPU target type is always same-as/similar-to underlying Host (i.e. Target CPU=Host).
This patch series implements KVM_ARM_PREFERRED_TARGET vm ioclt for querying VCPU target type matching underlying host. Using this new ioctl we can implement VCPU target CPU=Host in user space.
Also, it is not mandatory to call KVM_ARM_PREFERRED_TARGET vm ioctl and the old method of trying all possible target types using the KVM_ARM_VCPU_INIT ioctl to initialize VCPU works fine.
Looks good to me, as soon as Marc acks this one, I'll merge it.
Yup, go for it:
Acked-by: Marc Zyngier marc.zyngier@arm.com
Cool, merged in kvm-arm-next, tested with changes to experimental qemu mach-virt patches on vexpress TC2.
-Christoffer
linaro-kernel@lists.linaro.org
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Anup Patel -
Christoffer Dall -
Marc Zyngier