| Message ID | 20231012051509.738750-5-apatel@ventanamicro.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | RISC-V SBI debug console extension support | expand |
On Thu, Oct 12, 2023 at 10:45:05AM +0530, Anup Patel wrote: > The frozen SBI v2.0 specification defines the SBI debug console > (DBCN) extension which replaces the legacy SBI v0.1 console > functions namely sbi_console_getchar() and sbi_console_putchar(). > > The SBI DBCN extension needs to be emulated in the KVM user-space > (i.e. QEMU-KVM or KVMTOOL) so we forward SBI DBCN calls from KVM > guest to the KVM user-space which can then redirect the console > input/output to wherever it wants (e.g. telnet, file, stdio, etc). > > The SBI debug console is simply a early console available to KVM > guest for early prints and it does not intend to replace the proper > console devices such as 8250, VirtIO console, etc. > > Signed-off-by: Anup Patel <apatel@ventanamicro.com> > --- > arch/riscv/include/asm/kvm_vcpu_sbi.h | 1 + > arch/riscv/include/uapi/asm/kvm.h | 1 + > arch/riscv/kvm/vcpu_sbi.c | 4 ++++ > arch/riscv/kvm/vcpu_sbi_replace.c | 32 +++++++++++++++++++++++++++ > 4 files changed, 38 insertions(+) > > diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h > index c02bda5559d7..6a453f7f8b56 100644 > --- a/arch/riscv/include/asm/kvm_vcpu_sbi.h > +++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h > @@ -73,6 +73,7 @@ extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_ipi; > extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_rfence; > extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_srst; > extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_hsm; > +extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_dbcn; > extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_experimental; > extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_vendor; > > diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h > index 917d8cc2489e..60d3b21dead7 100644 > --- a/arch/riscv/include/uapi/asm/kvm.h > +++ b/arch/riscv/include/uapi/asm/kvm.h > @@ -156,6 +156,7 @@ enum KVM_RISCV_SBI_EXT_ID { > KVM_RISCV_SBI_EXT_PMU, > KVM_RISCV_SBI_EXT_EXPERIMENTAL, > KVM_RISCV_SBI_EXT_VENDOR, > + KVM_RISCV_SBI_EXT_DBCN, > KVM_RISCV_SBI_EXT_MAX, > }; > > diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c > index 1b1cee86efda..bb76c3cf633f 100644 > --- a/arch/riscv/kvm/vcpu_sbi.c > +++ b/arch/riscv/kvm/vcpu_sbi.c > @@ -66,6 +66,10 @@ static const struct kvm_riscv_sbi_extension_entry sbi_ext[] = { > .ext_idx = KVM_RISCV_SBI_EXT_PMU, > .ext_ptr = &vcpu_sbi_ext_pmu, > }, > + { > + .ext_idx = KVM_RISCV_SBI_EXT_DBCN, > + .ext_ptr = &vcpu_sbi_ext_dbcn, > + }, > { > .ext_idx = KVM_RISCV_SBI_EXT_EXPERIMENTAL, > .ext_ptr = &vcpu_sbi_ext_experimental, > diff --git a/arch/riscv/kvm/vcpu_sbi_replace.c b/arch/riscv/kvm/vcpu_sbi_replace.c > index 7c4d5d38a339..23b57c931b15 100644 > --- a/arch/riscv/kvm/vcpu_sbi_replace.c > +++ b/arch/riscv/kvm/vcpu_sbi_replace.c > @@ -175,3 +175,35 @@ const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_srst = { > .extid_end = SBI_EXT_SRST, > .handler = kvm_sbi_ext_srst_handler, > }; > + > +static int kvm_sbi_ext_dbcn_handler(struct kvm_vcpu *vcpu, > + struct kvm_run *run, > + struct kvm_vcpu_sbi_return *retdata) > +{ > + struct kvm_cpu_context *cp = &vcpu->arch.guest_context; > + unsigned long funcid = cp->a6; > + > + switch (funcid) { > + case SBI_EXT_DBCN_CONSOLE_WRITE: > + case SBI_EXT_DBCN_CONSOLE_READ: > + case SBI_EXT_DBCN_CONSOLE_WRITE_BYTE: > + /* > + * The SBI debug console functions are unconditionally > + * forwarded to the userspace. > + */ > + kvm_riscv_vcpu_sbi_forward(vcpu, run); > + retdata->uexit = true; > + break; > + default: > + retdata->err_val = SBI_ERR_NOT_SUPPORTED; > + } > + > + return 0; > +} > + > +const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_dbcn = { > + .extid_start = SBI_EXT_DBCN, > + .extid_end = SBI_EXT_DBCN, > + .default_unavail = true, > + .handler = kvm_sbi_ext_dbcn_handler, > +}; > -- > 2.34.1 > Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
On Thu, Oct 12, 2023 at 10:45:05AM +0530, Anup Patel wrote: > The frozen SBI v2.0 specification defines the SBI debug console > (DBCN) extension which replaces the legacy SBI v0.1 console > functions namely sbi_console_getchar() and sbi_console_putchar(). > > The SBI DBCN extension needs to be emulated in the KVM user-space > (i.e. QEMU-KVM or KVMTOOL) so we forward SBI DBCN calls from KVM > guest to the KVM user-space which can then redirect the console > input/output to wherever it wants (e.g. telnet, file, stdio, etc). > > The SBI debug console is simply a early console available to KVM > guest for early prints and it does not intend to replace the proper > console devices such as 8250, VirtIO console, etc. > > Signed-off-by: Anup Patel <apatel@ventanamicro.com> > --- > arch/riscv/include/asm/kvm_vcpu_sbi.h | 1 + > arch/riscv/include/uapi/asm/kvm.h | 1 + > arch/riscv/kvm/vcpu_sbi.c | 4 ++++ > arch/riscv/kvm/vcpu_sbi_replace.c | 32 +++++++++++++++++++++++++++ > 4 files changed, 38 insertions(+) > > diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h > index c02bda5559d7..6a453f7f8b56 100644 > --- a/arch/riscv/include/asm/kvm_vcpu_sbi.h > +++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h > @@ -73,6 +73,7 @@ extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_ipi; > extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_rfence; > extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_srst; > extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_hsm; > +extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_dbcn; > extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_experimental; > extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_vendor; > > diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h > index 917d8cc2489e..60d3b21dead7 100644 > --- a/arch/riscv/include/uapi/asm/kvm.h > +++ b/arch/riscv/include/uapi/asm/kvm.h > @@ -156,6 +156,7 @@ enum KVM_RISCV_SBI_EXT_ID { > KVM_RISCV_SBI_EXT_PMU, > KVM_RISCV_SBI_EXT_EXPERIMENTAL, > KVM_RISCV_SBI_EXT_VENDOR, > + KVM_RISCV_SBI_EXT_DBCN, We should add this new register to the get-reg-list kselftest, i.e. diff --git a/tools/testing/selftests/kvm/riscv/get-reg-list.c b/tools/testing/selftests/kvm/riscv/get-reg-list.c index 234006d035c9..4a0f8a8cfbf8 100644 --- a/tools/testing/selftests/kvm/riscv/get-reg-list.c +++ b/tools/testing/selftests/kvm/riscv/get-reg-list.c @@ -565,6 +565,7 @@ static __u64 base_regs[] = { KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_EXT | KVM_REG_RISCV_SBI_SINGLE | KVM_RISCV_SBI_EXT_SRST, KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_EXT | KVM_REG_RISCV_SBI_SINGLE | KVM_RISCV_SBI_EXT_HSM, KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_EXT | KVM_REG_RISCV_SBI_SINGLE | KVM_RISCV_SBI_EXT_PMU, + KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_EXT | KVM_REG_RISCV_SBI_SINGLE | KVM_RISCV_SBI_EXT_DBCN, KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_EXT | KVM_REG_RISCV_SBI_SINGLE | KVM_RISCV_SBI_EXT_EXPERIMENTAL, KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_EXT | KVM_REG_RISCV_SBI_SINGLE | KVM_RISCV_SBI_EXT_VENDOR, KVM_REG_RISCV | KVM_REG_SIZE_ULONG | KVM_REG_RISCV_SBI_EXT | KVM_REG_RISCV_SBI_MULTI_EN | 0, Thanks, drew
diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h index c02bda5559d7..6a453f7f8b56 100644 --- a/arch/riscv/include/asm/kvm_vcpu_sbi.h +++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h @@ -73,6 +73,7 @@ extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_ipi; extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_rfence; extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_srst; extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_hsm; +extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_dbcn; extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_experimental; extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_vendor; diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h index 917d8cc2489e..60d3b21dead7 100644 --- a/arch/riscv/include/uapi/asm/kvm.h +++ b/arch/riscv/include/uapi/asm/kvm.h @@ -156,6 +156,7 @@ enum KVM_RISCV_SBI_EXT_ID { KVM_RISCV_SBI_EXT_PMU, KVM_RISCV_SBI_EXT_EXPERIMENTAL, KVM_RISCV_SBI_EXT_VENDOR, + KVM_RISCV_SBI_EXT_DBCN, KVM_RISCV_SBI_EXT_MAX, }; diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c index 1b1cee86efda..bb76c3cf633f 100644 --- a/arch/riscv/kvm/vcpu_sbi.c +++ b/arch/riscv/kvm/vcpu_sbi.c @@ -66,6 +66,10 @@ static const struct kvm_riscv_sbi_extension_entry sbi_ext[] = { .ext_idx = KVM_RISCV_SBI_EXT_PMU, .ext_ptr = &vcpu_sbi_ext_pmu, }, + { + .ext_idx = KVM_RISCV_SBI_EXT_DBCN, + .ext_ptr = &vcpu_sbi_ext_dbcn, + }, { .ext_idx = KVM_RISCV_SBI_EXT_EXPERIMENTAL, .ext_ptr = &vcpu_sbi_ext_experimental, diff --git a/arch/riscv/kvm/vcpu_sbi_replace.c b/arch/riscv/kvm/vcpu_sbi_replace.c index 7c4d5d38a339..23b57c931b15 100644 --- a/arch/riscv/kvm/vcpu_sbi_replace.c +++ b/arch/riscv/kvm/vcpu_sbi_replace.c @@ -175,3 +175,35 @@ const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_srst = { .extid_end = SBI_EXT_SRST, .handler = kvm_sbi_ext_srst_handler, }; + +static int kvm_sbi_ext_dbcn_handler(struct kvm_vcpu *vcpu, + struct kvm_run *run, + struct kvm_vcpu_sbi_return *retdata) +{ + struct kvm_cpu_context *cp = &vcpu->arch.guest_context; + unsigned long funcid = cp->a6; + + switch (funcid) { + case SBI_EXT_DBCN_CONSOLE_WRITE: + case SBI_EXT_DBCN_CONSOLE_READ: + case SBI_EXT_DBCN_CONSOLE_WRITE_BYTE: + /* + * The SBI debug console functions are unconditionally + * forwarded to the userspace. + */ + kvm_riscv_vcpu_sbi_forward(vcpu, run); + retdata->uexit = true; + break; + default: + retdata->err_val = SBI_ERR_NOT_SUPPORTED; + } + + return 0; +} + +const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_dbcn = { + .extid_start = SBI_EXT_DBCN, + .extid_end = SBI_EXT_DBCN, + .default_unavail = true, + .handler = kvm_sbi_ext_dbcn_handler, +};
The frozen SBI v2.0 specification defines the SBI debug console (DBCN) extension which replaces the legacy SBI v0.1 console functions namely sbi_console_getchar() and sbi_console_putchar(). The SBI DBCN extension needs to be emulated in the KVM user-space (i.e. QEMU-KVM or KVMTOOL) so we forward SBI DBCN calls from KVM guest to the KVM user-space which can then redirect the console input/output to wherever it wants (e.g. telnet, file, stdio, etc). The SBI debug console is simply a early console available to KVM guest for early prints and it does not intend to replace the proper console devices such as 8250, VirtIO console, etc. Signed-off-by: Anup Patel <apatel@ventanamicro.com> --- arch/riscv/include/asm/kvm_vcpu_sbi.h | 1 + arch/riscv/include/uapi/asm/kvm.h | 1 + arch/riscv/kvm/vcpu_sbi.c | 4 ++++ arch/riscv/kvm/vcpu_sbi_replace.c | 32 +++++++++++++++++++++++++++ 4 files changed, 38 insertions(+)