Re: [PATCH 1/2] riscv: kvm: Add KVM_GET_REG_LIST API support

On Thu, May 11, 2023 at 6:44 PM Andrew Jones ajones@ventanamicro.com wrote:

On Thu, May 11, 2023 at 05:22:48PM +0800, Haibo Xu wrote:

...

KVM_GET_REG_LIST API will return all registers that are available to KVM_GET/SET_ONE_REG APIs. It's very useful to identify some platform regression issue during VM migration.

Since this API was already supported on arm64, it'd be straightforward

s/it'd be/it is/

...

to enable it on riscv with similar code structure.

Signed-off-by: Haibo Xu haibo1.xu@intel.com

Documentation/virt/kvm/api.rst | 2 +- arch/riscv/kvm/vcpu.c | 346 +++++++++++++++++++++++++++++++++ 2 files changed, 347 insertions(+), 1 deletion(-)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index add067793b90..280e89abd004 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -3499,7 +3499,7 @@ VCPU matching underlying host.

---

:Capability: basic -:Architectures: arm64, mips +:Architectures: arm64, mips, riscv :Type: vcpu ioctl :Parameters: struct kvm_reg_list (in/out) :Returns: 0 on success; -1 on error diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 8bd9f2a8a0b9..fb8834e4fa15 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -657,6 +657,334 @@ static int kvm_riscv_vcpu_set_reg_isa_ext(struct kvm_vcpu *vcpu, return 0; }

+static inline unsigned long num_config_regs(void) +{

• return sizeof(struct kvm_riscv_config) / sizeof(unsigned long);
  

+}

+static int copy_config_reg_indices(u64 __user *uindices) +{

• unsigned int i;
  

• int n = num_config_regs();
  

• for (i = 0; i < n; i++) {
  

•         u64 reg = KVM_REG_RISCV | KVM_REG_SIZE_U64 | KVM_REG_RISCV_CONFIG | i;
  

                                      ^ this should be
                                      size-ulong

u64 size = IS_ENABLED(CONFIG_32BIT) ? KVM_REG_SIZE_U32 : KVM_REG_SIZE_U64; u64 reg = KVM_REG_RISCV | size | KVM_REG_RISCV_CONFIG | i;

...

•         if (uindices) {
  

•                 if (put_user(reg, uindices))
  

•                         return -EFAULT;
  

•                 uindices++;
  

•         }
  

• }
  

• return n;
  

+}

+static inline unsigned long num_core_regs(void) +{

• return sizeof(struct kvm_riscv_core) / sizeof(unsigned long);
  

+}

+static int copy_core_reg_indices(u64 __user *uindices) +{

• unsigned int i;
  

• int n = num_core_regs();
  

• for (i = 0; i < n; i++) {
  

•         u64 reg = KVM_REG_RISCV | KVM_REG_SIZE_U64 | KVM_REG_RISCV_CORE | i;
  

                                      ^ size-ulong

...

•         if (uindices) {
  

•                 if (put_user(reg, uindices))
  

•                         return -EFAULT;
  

•                 uindices++;
  

•         }
  

• }
  

• return n;
  

+}

+static inline unsigned long num_csr_regs(void) +{

• unsigned long n = sizeof(struct kvm_riscv_csr) / sizeof(unsigned long);
  

• if (kvm_riscv_aia_available())
  

•         n += sizeof(struct kvm_riscv_aia_csr) / sizeof(unsigned long);
  

• return n;
  

+}

+static int copy_csr_reg_indices(u64 __user *uindices) +{

• unsigned int i;
  

• int n1 = sizeof(struct kvm_riscv_csr) / sizeof(unsigned long);
  

• int n2 = 0;
  

• /* copy general csr regs */
  

• for (i = 0; i < n1; i++) {
  

•         u64 reg = KVM_REG_RISCV | KVM_REG_SIZE_U64 | KVM_REG_RISCV_CSR |
  

                                      ^ size-ulong

...

•                           KVM_REG_RISCV_CSR_GENERAL | i;
  

•         if (uindices) {
  

•                 if (put_user(reg, uindices))
  

•                         return -EFAULT;
  

•                 uindices++;
  

•         }
  

• }
  

• /* copy AIA csr regs */
  

• if (kvm_riscv_aia_available()) {
  

•         n2 = sizeof(struct kvm_riscv_aia_csr) / sizeof(unsigned long);
  

•         for (i = 0; i < n2; i++) {
  

•                 u64 reg = KVM_REG_RISCV | KVM_REG_SIZE_U64 | KVM_REG_RISCV_CSR |
  

                                              ^ size-ulong

...

•                                   KVM_REG_RISCV_CSR_AIA | i;
  

•                 if (uindices) {
  

•                         if (put_user(reg, uindices))
  

•                                 return -EFAULT;
  

•                         uindices++;
  

•                 }
  

•         }
  

• }
  

• return n1 + n2;
  

+}

+static inline unsigned long num_timer_regs(void) +{

• return sizeof(struct kvm_riscv_timer) / sizeof(unsigned long);
  

+}

+static int copy_timer_reg_indices(u64 __user *uindices) +{

• unsigned int i;
  

• int n = num_timer_regs();
  

• for (i = 0; i < n; i++) {
  

•         u64 reg = KVM_REG_RISCV | KVM_REG_SIZE_U64 | KVM_REG_RISCV_TIMER | i;
  

•         if (uindices) {
  

•                 if (put_user(reg, uindices))
  

•                         return -EFAULT;
  

•                 uindices++;
  

•         }
  

• }
  

• return n;
  

+}

+static inline unsigned long num_fp_f_regs(const struct kvm_vcpu *vcpu) +{

• const struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
  

• if (riscv_isa_extension_available(vcpu->arch.isa, f))
  

•         return sizeof(cntx->fp.f) / sizeof(u32);
  

• else
  

•         return 0;
  

+}

+static int copy_fp_f_reg_indices(const struct kvm_vcpu *vcpu,

•                                 u64 __user *uindices)
  

+{

• unsigned int i;
  

• int n = num_fp_f_regs(vcpu);
  

• for (i = 0; i < n; i++) {
  

•         u64 reg = KVM_REG_RISCV | KVM_REG_SIZE_U32 | KVM_REG_RISCV_FP_F | i;
  

•         if (uindices) {
  

•                 if (put_user(reg, uindices))
  

•                         return -EFAULT;
  

•                 uindices++;
  

•         }
  

• }
  

• return n;
  

+}

+static inline unsigned long num_fp_d_regs(const struct kvm_vcpu *vcpu) +{

• const struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
  

• if (riscv_isa_extension_available(vcpu->arch.isa, d))
  

•         return sizeof(cntx->fp.d.f) / sizeof(u64) + 1;
  

• else
  

•         return 0;
  

+}

+static int copy_fp_d_reg_indices(const struct kvm_vcpu *vcpu,

•                                 u64 __user *uindices)
  

+{

• unsigned int i;
  

• int n = num_fp_d_regs(vcpu);
  

• u64 reg;
  

• /* copy fp.d.f indeices */
  

indices

...

• for (i = 0; i < n-1; i++) {
  

•         reg = KVM_REG_RISCV | KVM_REG_SIZE_U64 | KVM_REG_RISCV_FP_D | i;
  

•         if (uindices) {
  

•                 if (put_user(reg, uindices))
  

•                         return -EFAULT;
  

•                 uindices++;
  

•         }
  

• }
  

• /* copy fp.d.fcsr indeices */
  

indices

...

• reg = KVM_REG_RISCV | KVM_REG_SIZE_U32 | KVM_REG_RISCV_FP_D | i;
  

• if (uindices) {
  

•         if (put_user(reg, uindices))
  

•                 return -EFAULT;
  

• }
  

• return n;
  

+}

+static inline unsigned long num_isa_ext_regs(void) +{

• return KVM_RISCV_ISA_EXT_MAX;
  

+}

+static int copy_isa_ext_reg_indices(u64 __user *uindices) +{

• unsigned int i;
  

• int n = num_isa_ext_regs();
  

• for (i = 0; i < n; i++) {
  

•         u64 reg = KVM_REG_RISCV | KVM_REG_SIZE_U64 | KVM_REG_RISCV_ISA_EXT | i;
  

                                      ^ size-ulong

...

•         if (uindices) {
  

•                 if (put_user(reg, uindices))
  

•                         return -EFAULT;
  

•                 uindices++;
  

•         }
  

• }
  

• return n;
  

+}

+static inline unsigned long num_sbi_ext_regs(void) +{

• /* number of KVM_REG_RISCV_SBI_SINGLE +
  

•  *  2x(number of KVM_REG_RISCV_SBI_MULTI)
  

•  */
  

Please use an opening wing '/*' on comments.

...

• return KVM_RISCV_SBI_EXT_MAX + 2*(KVM_REG_RISCV_SBI_MULTI_REG_LAST+1);
  

+}

+static int copy_sbi_ext_reg_indices(u64 __user *uindices) +{

• unsigned int i;
  

• int n;
  

• /* copy KVM_REG_RISCV_SBI_SINGLE */
  

• n = KVM_RISCV_SBI_EXT_MAX;
  

• for (i = 0; i < n; i++) {
  

•         u64 reg = KVM_REG_RISCV | KVM_REG_SIZE_U64 | KVM_REG_RISCV_SBI_EXT |
  

                                      ^ size-ulong

...

•                           KVM_REG_RISCV_SBI_SINGLE | i;
  

•         if (uindices) {
  

•                 if (put_user(reg, uindices))
  

•                         return -EFAULT;
  

•                 uindices++;
  

•         }
  

• }
  

• /* copy KVM_REG_RISCV_SBI_MULTI */
  

• n = KVM_REG_RISCV_SBI_MULTI_REG_LAST + 1;
  

• for (i = 0; i < n; i++) {
  

•         u64 reg = KVM_REG_RISCV | KVM_REG_SIZE_U64 | KVM_REG_RISCV_SBI_EXT |
  

                                      ^ size-ulong

...

•                           KVM_REG_RISCV_SBI_MULTI_EN | i;
  

•         if (uindices) {
  

•                 if (put_user(reg, uindices))
  

•                         return -EFAULT;
  

•                 uindices++;
  

•         }
  

•         reg = KVM_REG_RISCV | KVM_REG_SIZE_U64 | KVM_REG_RISCV_SBI_EXT |
  

•                   KVM_REG_RISCV_SBI_MULTI_DIS | i;
  

•         if (uindices) {
  

•                 if (put_user(reg, uindices))
  

•                         return -EFAULT;
  

•                 uindices++;
  

•         }
  

• }
  

• return num_sbi_ext_regs();
  

+}

+/**

• • kvm_riscv_vcpu_num_regs - how many registers do we present via KVM_GET/SET_ONE_REG
• • This is for all registers.
• */

+static unsigned long kvm_riscv_vcpu_num_regs(struct kvm_vcpu *vcpu) +{

• unsigned long res = 0;
  

• res += num_config_regs();
  

• res += num_core_regs();
  

• res += num_csr_regs();
  

• res += num_timer_regs();
  

• res += num_fp_f_regs(vcpu);
  

• res += num_fp_d_regs(vcpu);
  

• res += num_isa_ext_regs();
  

• res += num_sbi_ext_regs();
  

• return res;
  

+}

+/**

• • kvm_riscv_vcpu_copy_reg_indices - get indices of all registers.
• */

+static int kvm_riscv_vcpu_copy_reg_indices(struct kvm_vcpu *vcpu,

•                         u64 __user *uindices)
  

+{

• int ret;
  

• ret = copy_config_reg_indices(uindices);
  

• if (ret < 0)
  

•         return ret;
  

• uindices += ret;
  

• ret = copy_core_reg_indices(uindices);
  

• if (ret < 0)
  

•         return ret;
  

• uindices += ret;
  

• ret = copy_csr_reg_indices(uindices);
  

• if (ret < 0)
  

•         return ret;
  

• uindices += ret;
  

• ret = copy_timer_reg_indices(uindices);
  

• if (ret < 0)
  

•         return ret;
  

• uindices += ret;
  

• ret = copy_fp_f_reg_indices(vcpu, uindices);
  

• if (ret < 0)
  

•         return ret;
  

• uindices += ret;
  

• ret = copy_fp_d_reg_indices(vcpu, uindices);
  

• if (ret < 0)
  

•         return ret;
  

• uindices += ret;
  

• ret = copy_isa_ext_reg_indices(uindices);
  

• if (ret < 0)
  

•         return ret;
  

• uindices += ret;
  

• ret = copy_sbi_ext_reg_indices(uindices);
  

• if (ret < 0)
  

•         return ret;
  

• return 0;
  

+}

static int kvm_riscv_vcpu_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) { @@ -758,6 +1086,24 @@ long kvm_arch_vcpu_ioctl(struct file *filp, r = kvm_riscv_vcpu_get_reg(vcpu, &reg); break; }

• case KVM_GET_REG_LIST: {
  

•         struct kvm_reg_list __user *user_list = argp;
  

•         struct kvm_reg_list reg_list;
  

•         unsigned int n;
  

•         r = -EFAULT;
  

•         if (copy_from_user(&reg_list, user_list, sizeof(reg_list)))
  

•                 break;
  

•         n = reg_list.n;
  

•         reg_list.n = kvm_riscv_vcpu_num_regs(vcpu);
  

•         if (copy_to_user(user_list, &reg_list, sizeof(reg_list)))
  

•                 break;
  

•         r = -E2BIG;
  

•         if (n < reg_list.n)
  

•                 break;
  

•         r = kvm_riscv_vcpu_copy_reg_indices(vcpu, user_list->reg);
  

•         break;
  

• }
  default:
          break;
  }
  

-- 2.34.1

Otherwise,

Reviewed-by: Andrew Jones ajones@ventanamicro.com

Thanks, drew

Thanks for your review, Andrew! The comments will be addressed in next version.