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path: root/arch/riscv/kvm/vcpu_sbi_replace.c
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2023-12-29RISC-V: KVM: Make SBI uapi consistent with ISA uapiAndrew Jones1-1/+1
When an SBI extension cannot be enabled, that's a distinct state vs. enabled and disabled. Modify enum kvm_riscv_sbi_ext_status to accommodate it, which allows KVM userspace to tell the difference in state too, as the SBI extension register will disappear when it cannot be enabled, i.e. accesses to it return ENOENT. get-reg-list is updated as well to only add SBI extension registers to the list which may be enabled. Returning ENOENT for SBI extension registers which cannot be enabled makes them consistent with ISA extension registers. Any SBI extensions which were enabled by default are still enabled by default, if they can be enabled at all. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Anup Patel <anup@brainfault.org>
2023-10-20RISC-V: KVM: Forward SBI DBCN extension to user-spaceAnup Patel1-0/+32
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> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2023-02-07RISC-V: KVM: Increment firmware pmu eventsAtish Patra1-0/+7
KVM supports firmware events now. Invoke the firmware event increment function from appropriate places. Reviewed-by: Anup Patel <anup@brainfault.org> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2023-02-07RISC-V: KVM: Modify SBI extension handler to return SBI error codeAtish Patra1-23/+20
Currently, the SBI extension handle is expected to return Linux error code. The top SBI layer converts the Linux error code to SBI specific error code that can be returned to guest invoking the SBI calls. This model works as long as SBI error codes have 1-to-1 mappings between them. However, that may not be true always. This patch attempts to disassociate both these error codes by allowing the SBI extension implementation to return SBI specific error codes as well. The extension will continue to return the Linux error specific code which will indicate any problem *with* the extension emulation while the SBI specific error will indicate the problem *of* the emulation. Reviewed-by: Anup Patel <anup@brainfault.org> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Suggested-by: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2022-12-07RISC-V: KVM: Remove redundant includes of asm/csr.hAnup Patel1-1/+0
We should include asm/csr.h only where required so let us remove redundant includes of this header. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2022-05-20RISC-V: KVM: Add remote HFENCE functions based on VCPU requestsAnup Patel1-20/+14
The generic KVM has support for VCPU requests which can be used to do arch-specific work in the run-loop. We introduce remote HFENCE functions which will internally use VCPU requests instead of host SBI calls. Advantages of doing remote HFENCEs as VCPU requests are: 1) Multiple VCPUs of a Guest may be running on different Host CPUs so it is not always possible to determine the Host CPU mask for doing Host SBI call. For example, when VCPU X wants to do HFENCE on VCPU Y, it is possible that VCPU Y is blocked or in user-space (i.e. vcpu->cpu < 0). 2) To support nested virtualization, we will be having a separate shadow G-stage for each VCPU and a common host G-stage for the entire Guest/VM. The VCPU requests based remote HFENCEs helps us easily synchronize the common host G-stage and shadow G-stage of each VCPU without any additional IPI calls. This is also a preparatory patch for upcoming nested virtualization support where we will be having a shadow G-stage page table for each Guest VCPU. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2022-05-20RISC-V: KVM: Treat SBI HFENCE calls as NOPsAnup Patel1-1/+5
We should treat SBI HFENCE calls as NOPs until nested virtualization is supported by KVM RISC-V. This will help us test booting a hypervisor under KVM RISC-V. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2022-03-11RISC-V: KVM: Implement SBI v0.3 SRST extensionAnup Patel1-0/+44
The SBI v0.3 specification defines SRST (System Reset) extension which provides a standard poweroff and reboot interface. This patch implements SRST extension for the KVM Guest. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2022-01-20RISC-V: Do not use cpumask data structure for hartid bitmapAtish Patra1-7/+4
Currently, SBI APIs accept a hartmask that is generated from struct cpumask. Cpumask data structure can hold upto NR_CPUs value. Thus, it is not the correct data structure for hartids as it can be higher than NR_CPUs for platforms with sparse or discontguous hartids. Remove all association between hartid mask and struct cpumask. Reviewed-by: Anup Patel <anup@brainfault.org> (For Linux RISC-V changes) Acked-by: Anup Patel <anup@brainfault.org> (For KVM RISC-V changes) Signed-off-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-06RISC-V: KVM: Add v0.1 replacement SBI extensions defined in v0.2Atish Patra1-0/+135
The SBI v0.2 contains some of the improved versions of required v0.1 extensions such as remote fence, timer and IPI. This patch implements those extensions. Signed-off-by: Atish Patra <atish.patra@wdc.com> Signed-off-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup.patel@wdc.com>