From fdf68acccfc6af9497c34ee411d89af13b6516ed Mon Sep 17 00:00:00 2001 From: Andrew Jones Date: Wed, 20 Dec 2023 17:00:16 +0100 Subject: RISC-V: paravirt: Implement steal-time support When the SBI STA extension exists we can use it to implement paravirt steal-time support. Fill in the empty pv-time functions with an SBI STA implementation and add the Kconfig knobs allowing it to be enabled. Acked-by: Palmer Dabbelt Reviewed-by: Atish Patra Reviewed-by: Anup Patel Signed-off-by: Andrew Jones Signed-off-by: Anup Patel --- arch/riscv/Kconfig | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'arch/riscv/Kconfig') diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 24c1799e2ec4..ef8b7b012a0b 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -724,6 +724,25 @@ config COMPAT If you want to execute 32-bit userspace applications, say Y. +config PARAVIRT + bool "Enable paravirtualization code" + depends on RISCV_SBI + help + This changes the kernel so it can modify itself when it is run + under a hypervisor, potentially improving performance significantly + over full virtualization. + +config PARAVIRT_TIME_ACCOUNTING + bool "Paravirtual steal time accounting" + depends on PARAVIRT + help + Select this option to enable fine granularity task steal time + accounting. Time spent executing other tasks in parallel with + the current vCPU is discounted from the vCPU power. To account for + that, there can be a small performance impact. + + If in doubt, say N here. + config RELOCATABLE bool "Build a relocatable kernel" depends on MMU && 64BIT && !XIP_KERNEL -- cgit v1.2.3