RISC-V: KVM: return ENOENT in *_one_reg() when reg is unknown

get_one_reg() and set_one_reg() are returning EINVAL errors for almost
everything: if a reg doesn't exist, if a reg ID is malformatted, if the
associated CPU extension that implements the reg isn't present in the
host, and for set_one_reg() if the value being written is invalid.

This isn't wrong according to the existing KVM API docs (EINVAL can be
used when there's no such register) but adding more ENOENT instances
will make easier for userspace to understand what went wrong.

Existing userspaces can be affected by this error code change. We
checked a few. As of current upstream code, crosvm doesn't check for any
particular errno code when using kvm_(get|set)_one_reg(). Neither does
QEMU. rust-vmm doesn't have kvm-riscv support yet. Thus we have a good
chance of changing these error codes now while the KVM RISC-V ecosystem
is still new, minimizing user impact.

Change all get_one_reg() and set_one_reg() implementations to return
-ENOENT at all "no such register" cases.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>

diff --git a/arch/riscv/kvm/aia.c b/arch/riscv/kvm/aia.c
index 585a3b42c52c69cc34662d9740e4378fcc475147..74bb27440527b3bafa1418fc75337162e9bc3589 100644 (file)
--- a/arch/riscv/kvm/aia.c
+++ b/arch/riscv/kvm/aia.c
@@ -176,7 +176,7 @@ int kvm_riscv_vcpu_aia_get_csr(struct kvm_vcpu *vcpu,
        struct kvm_vcpu_aia_csr *csr = &vcpu->arch.aia_context.guest_csr;
 
        if (reg_num >= sizeof(struct kvm_riscv_aia_csr) / sizeof(unsigned long))
-               return -EINVAL;
+               return -ENOENT;
 
        *out_val = 0;
        if (kvm_riscv_aia_available())
@@ -192,7 +192,7 @@ int kvm_riscv_vcpu_aia_set_csr(struct kvm_vcpu *vcpu,
        struct kvm_vcpu_aia_csr *csr = &vcpu->arch.aia_context.guest_csr;
 
        if (reg_num >= sizeof(struct kvm_riscv_aia_csr) / sizeof(unsigned long))
-               return -EINVAL;
+               return -ENOENT;
 
        if (kvm_riscv_aia_available()) {
                ((unsigned long *)csr)[reg_num] = val;

diff --git a/arch/riscv/kvm/vcpu_fp.c b/arch/riscv/kvm/vcpu_fp.c
index 9d8cbc42057a92b1bcffe3ef339fbfed253ef8ae..08ba48a395aa2a232bd00755f02355e6770d0ee7 100644 (file)
--- a/arch/riscv/kvm/vcpu_fp.c
+++ b/arch/riscv/kvm/vcpu_fp.c
@@ -96,7 +96,7 @@ int kvm_riscv_vcpu_get_reg_fp(struct kvm_vcpu *vcpu,
                          reg_num <= KVM_REG_RISCV_FP_F_REG(f[31]))
                        reg_val = &cntx->fp.f.f[reg_num];
                else
-                       return -EINVAL;
+                       return -ENOENT;
        } else if ((rtype == KVM_REG_RISCV_FP_D) &&
                   riscv_isa_extension_available(vcpu->arch.isa, d)) {
                if (reg_num == KVM_REG_RISCV_FP_D_REG(fcsr)) {
@@ -109,9 +109,9 @@ int kvm_riscv_vcpu_get_reg_fp(struct kvm_vcpu *vcpu,
                                return -EINVAL;
                        reg_val = &cntx->fp.d.f[reg_num];
                } else
-                       return -EINVAL;
+                       return -ENOENT;
        } else
-               return -EINVAL;
+               return -ENOENT;
 
        if (copy_to_user(uaddr, reg_val, KVM_REG_SIZE(reg->id)))
                return -EFAULT;
@@ -141,7 +141,7 @@ int kvm_riscv_vcpu_set_reg_fp(struct kvm_vcpu *vcpu,
                          reg_num <= KVM_REG_RISCV_FP_F_REG(f[31]))
                        reg_val = &cntx->fp.f.f[reg_num];
                else
-                       return -EINVAL;
+                       return -ENOENT;
        } else if ((rtype == KVM_REG_RISCV_FP_D) &&
                   riscv_isa_extension_available(vcpu->arch.isa, d)) {
                if (reg_num == KVM_REG_RISCV_FP_D_REG(fcsr)) {
@@ -154,9 +154,9 @@ int kvm_riscv_vcpu_set_reg_fp(struct kvm_vcpu *vcpu,
                                return -EINVAL;
                        reg_val = &cntx->fp.d.f[reg_num];
                } else
-                       return -EINVAL;
+                       return -ENOENT;
        } else
-               return -EINVAL;
+               return -ENOENT;
 
        if (copy_from_user(reg_val, uaddr, KVM_REG_SIZE(reg->id)))
                return -EFAULT;

diff --git a/arch/riscv/kvm/vcpu_onereg.c b/arch/riscv/kvm/vcpu_onereg.c
index 85773e858120f8049630d1e4b92b95f08a2e4c89..456e9f31441a4e26d5685d62cb9eb45065e57735 100644 (file)
--- a/arch/riscv/kvm/vcpu_onereg.c
+++ b/arch/riscv/kvm/vcpu_onereg.c
@@ -156,7 +156,7 @@ static int kvm_riscv_vcpu_get_reg_config(struct kvm_vcpu *vcpu,
                reg_val = satp_mode >> SATP_MODE_SHIFT;
                break;
        default:
-               return -EINVAL;
+               return -ENOENT;
        }
 
        if (copy_to_user(uaddr, &reg_val, KVM_REG_SIZE(reg->id)))
@@ -242,7 +242,7 @@ static int kvm_riscv_vcpu_set_reg_config(struct kvm_vcpu *vcpu,
                        return -EINVAL;
                break;
        default:
-               return -EINVAL;
+               return -ENOENT;
        }
 
        return 0;
@@ -262,7 +262,7 @@ static int kvm_riscv_vcpu_get_reg_core(struct kvm_vcpu *vcpu,
        if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
                return -EINVAL;
        if (reg_num >= sizeof(struct kvm_riscv_core) / sizeof(unsigned long))
-               return -EINVAL;
+               return -ENOENT;
 
        if (reg_num == KVM_REG_RISCV_CORE_REG(regs.pc))
                reg_val = cntx->sepc;
@@ -273,7 +273,7 @@ static int kvm_riscv_vcpu_get_reg_core(struct kvm_vcpu *vcpu,
                reg_val = (cntx->sstatus & SR_SPP) ?
                                KVM_RISCV_MODE_S : KVM_RISCV_MODE_U;
        else
-               return -EINVAL;
+               return -ENOENT;
 
        if (copy_to_user(uaddr, &reg_val, KVM_REG_SIZE(reg->id)))
                return -EFAULT;
@@ -295,7 +295,7 @@ static int kvm_riscv_vcpu_set_reg_core(struct kvm_vcpu *vcpu,
        if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
                return -EINVAL;
        if (reg_num >= sizeof(struct kvm_riscv_core) / sizeof(unsigned long))
-               return -EINVAL;
+               return -ENOENT;
 
        if (copy_from_user(&reg_val, uaddr, KVM_REG_SIZE(reg->id)))
                return -EFAULT;
@@ -311,7 +311,7 @@ static int kvm_riscv_vcpu_set_reg_core(struct kvm_vcpu *vcpu,
                else
                        cntx->sstatus &= ~SR_SPP;
        } else
-               return -EINVAL;
+               return -ENOENT;
 
        return 0;
 }
@@ -323,7 +323,7 @@ static int kvm_riscv_vcpu_general_get_csr(struct kvm_vcpu *vcpu,
        struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
 
        if (reg_num >= sizeof(struct kvm_riscv_csr) / sizeof(unsigned long))
-               return -EINVAL;
+               return -ENOENT;
 
        if (reg_num == KVM_REG_RISCV_CSR_REG(sip)) {
                kvm_riscv_vcpu_flush_interrupts(vcpu);
@@ -342,7 +342,7 @@ static int kvm_riscv_vcpu_general_set_csr(struct kvm_vcpu *vcpu,
        struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
 
        if (reg_num >= sizeof(struct kvm_riscv_csr) / sizeof(unsigned long))
-               return -EINVAL;
+               return -ENOENT;
 
        if (reg_num == KVM_REG_RISCV_CSR_REG(sip)) {
                reg_val &= VSIP_VALID_MASK;
@@ -381,7 +381,7 @@ static int kvm_riscv_vcpu_get_reg_csr(struct kvm_vcpu *vcpu,
                rc = kvm_riscv_vcpu_aia_get_csr(vcpu, reg_num, &reg_val);
                break;
        default:
-               rc = -EINVAL;
+               rc = -ENOENT;
                break;
        }
        if (rc)
@@ -420,7 +420,7 @@ static int kvm_riscv_vcpu_set_reg_csr(struct kvm_vcpu *vcpu,
                rc = kvm_riscv_vcpu_aia_set_csr(vcpu, reg_num, reg_val);
                break;
        default:
-               rc = -EINVAL;
+               rc = -ENOENT;
                break;
        }
        if (rc)
@@ -437,7 +437,7 @@ static int riscv_vcpu_get_isa_ext_single(struct kvm_vcpu *vcpu,
 
        if (reg_num >= KVM_RISCV_ISA_EXT_MAX ||
            reg_num >= ARRAY_SIZE(kvm_isa_ext_arr))
-               return -EINVAL;
+               return -ENOENT;
 
        *reg_val = 0;
        host_isa_ext = kvm_isa_ext_arr[reg_num];
@@ -455,7 +455,7 @@ static int riscv_vcpu_set_isa_ext_single(struct kvm_vcpu *vcpu,
 
        if (reg_num >= KVM_RISCV_ISA_EXT_MAX ||
            reg_num >= ARRAY_SIZE(kvm_isa_ext_arr))
-               return -EINVAL;
+               return -ENOENT;
 
        host_isa_ext = kvm_isa_ext_arr[reg_num];
        if (!__riscv_isa_extension_available(NULL, host_isa_ext))
@@ -489,7 +489,7 @@ static int riscv_vcpu_get_isa_ext_multi(struct kvm_vcpu *vcpu,
        unsigned long i, ext_id, ext_val;
 
        if (reg_num > KVM_REG_RISCV_ISA_MULTI_REG_LAST)
-               return -EINVAL;
+               return -ENOENT;
 
        for (i = 0; i < BITS_PER_LONG; i++) {
                ext_id = i + reg_num * BITS_PER_LONG;
@@ -512,7 +512,7 @@ static int riscv_vcpu_set_isa_ext_multi(struct kvm_vcpu *vcpu,
        unsigned long i, ext_id;
 
        if (reg_num > KVM_REG_RISCV_ISA_MULTI_REG_LAST)
-               return -EINVAL;
+               return -ENOENT;
 
        for_each_set_bit(i, &reg_val, BITS_PER_LONG) {
                ext_id = i + reg_num * BITS_PER_LONG;
@@ -554,7 +554,7 @@ static int kvm_riscv_vcpu_get_reg_isa_ext(struct kvm_vcpu *vcpu,
                        reg_val = ~reg_val;
                break;
        default:
-               rc = -EINVAL;
+               rc = -ENOENT;
        }
        if (rc)
                return rc;
@@ -592,7 +592,7 @@ static int kvm_riscv_vcpu_set_reg_isa_ext(struct kvm_vcpu *vcpu,
        case KVM_REG_RISCV_SBI_MULTI_DIS:
                return riscv_vcpu_set_isa_ext_multi(vcpu, reg_num, reg_val, false);
        default:
-               return -EINVAL;
+               return -ENOENT;
        }
 
        return 0;
@@ -627,7 +627,7 @@ int kvm_riscv_vcpu_set_reg(struct kvm_vcpu *vcpu,
                break;
        }
 
-       return -EINVAL;
+       return -ENOENT;
 }
 
 int kvm_riscv_vcpu_get_reg(struct kvm_vcpu *vcpu,
@@ -659,5 +659,5 @@ int kvm_riscv_vcpu_get_reg(struct kvm_vcpu *vcpu,
                break;
        }
 
-       return -EINVAL;
+       return -ENOENT;
 }

diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
index 7b46e04fb6675cbe9fea91955ee5b74060462614..9cd97091c7233089ff71207c6da8280f2bcba0c6 100644 (file)
--- a/arch/riscv/kvm/vcpu_sbi.c
+++ b/arch/riscv/kvm/vcpu_sbi.c
@@ -140,8 +140,10 @@ static int riscv_vcpu_set_sbi_ext_single(struct kvm_vcpu *vcpu,
        const struct kvm_riscv_sbi_extension_entry *sext = NULL;
        struct kvm_vcpu_sbi_context *scontext = &vcpu->arch.sbi_context;
 
-       if (reg_num >= KVM_RISCV_SBI_EXT_MAX ||
-           (reg_val != 1 && reg_val != 0))
+       if (reg_num >= KVM_RISCV_SBI_EXT_MAX)
+               return -ENOENT;
+
+       if (reg_val != 1 && reg_val != 0)
                return -EINVAL;
 
        for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {
@@ -175,7 +177,7 @@ static int riscv_vcpu_get_sbi_ext_single(struct kvm_vcpu *vcpu,
        struct kvm_vcpu_sbi_context *scontext = &vcpu->arch.sbi_context;
 
        if (reg_num >= KVM_RISCV_SBI_EXT_MAX)
-               return -EINVAL;
+               return -ENOENT;
 
        for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {
                if (sbi_ext[i].ext_idx == reg_num) {
@@ -206,7 +208,7 @@ static int riscv_vcpu_set_sbi_ext_multi(struct kvm_vcpu *vcpu,
        unsigned long i, ext_id;
 
        if (reg_num > KVM_REG_RISCV_SBI_MULTI_REG_LAST)
-               return -EINVAL;
+               return -ENOENT;
 
        for_each_set_bit(i, &reg_val, BITS_PER_LONG) {
                ext_id = i + reg_num * BITS_PER_LONG;
@@ -226,7 +228,7 @@ static int riscv_vcpu_get_sbi_ext_multi(struct kvm_vcpu *vcpu,
        unsigned long i, ext_id, ext_val;
 
        if (reg_num > KVM_REG_RISCV_SBI_MULTI_REG_LAST)
-               return -EINVAL;
+               return -ENOENT;
 
        for (i = 0; i < BITS_PER_LONG; i++) {
                ext_id = i + reg_num * BITS_PER_LONG;
@@ -272,7 +274,7 @@ int kvm_riscv_vcpu_set_reg_sbi_ext(struct kvm_vcpu *vcpu,
        case KVM_REG_RISCV_SBI_MULTI_DIS:
                return riscv_vcpu_set_sbi_ext_multi(vcpu, reg_num, reg_val, false);
        default:
-               return -EINVAL;
+               return -ENOENT;
        }
 
        return 0;
@@ -307,7 +309,7 @@ int kvm_riscv_vcpu_get_reg_sbi_ext(struct kvm_vcpu *vcpu,
                        reg_val = ~reg_val;
                break;
        default:
-               rc = -EINVAL;
+               rc = -ENOENT;
        }
        if (rc)
                return rc;

diff --git a/arch/riscv/kvm/vcpu_timer.c b/arch/riscv/kvm/vcpu_timer.c
index 3ac2ff6a65dacbeb1e5c030602bef10962ecbb21..527d269cafffc48dc9780166887ed2e68d470d38 100644 (file)
--- a/arch/riscv/kvm/vcpu_timer.c
+++ b/arch/riscv/kvm/vcpu_timer.c
@@ -170,7 +170,7 @@ int kvm_riscv_vcpu_get_reg_timer(struct kvm_vcpu *vcpu,
        if (KVM_REG_SIZE(reg->id) != sizeof(u64))
                return -EINVAL;
        if (reg_num >= sizeof(struct kvm_riscv_timer) / sizeof(u64))
-               return -EINVAL;
+               return -ENOENT;
 
        switch (reg_num) {
        case KVM_REG_RISCV_TIMER_REG(frequency):
@@ -187,7 +187,7 @@ int kvm_riscv_vcpu_get_reg_timer(struct kvm_vcpu *vcpu,
                                          KVM_RISCV_TIMER_STATE_OFF;
                break;
        default:
-               return -EINVAL;
+               return -ENOENT;
        }
 
        if (copy_to_user(uaddr, &reg_val, KVM_REG_SIZE(reg->id)))
@@ -211,7 +211,7 @@ int kvm_riscv_vcpu_set_reg_timer(struct kvm_vcpu *vcpu,
        if (KVM_REG_SIZE(reg->id) != sizeof(u64))
                return -EINVAL;
        if (reg_num >= sizeof(struct kvm_riscv_timer) / sizeof(u64))
-               return -EINVAL;
+               return -ENOENT;
 
        if (copy_from_user(&reg_val, uaddr, KVM_REG_SIZE(reg->id)))
                return -EFAULT;
@@ -233,7 +233,7 @@ int kvm_riscv_vcpu_set_reg_timer(struct kvm_vcpu *vcpu,
                        ret = kvm_riscv_vcpu_timer_cancel(t);
                break;
        default:
-               ret = -EINVAL;
+               ret = -ENOENT;
                break;
        }