13acfec2db
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>
119 lines
2.9 KiB
C
119 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2021 Western Digital Corporation or its affiliates.
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*
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* Authors:
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* Atish Patra <atish.patra@wdc.com>
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*/
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#include <linux/errno.h>
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#include <linux/err.h>
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#include <linux/kvm_host.h>
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#include <asm/csr.h>
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#include <asm/sbi.h>
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#include <asm/kvm_vcpu_timer.h>
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#include <asm/kvm_vcpu_sbi.h>
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static int kvm_sbi_ext_v01_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
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unsigned long *out_val,
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struct kvm_cpu_trap *utrap,
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bool *exit)
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{
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ulong hmask;
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int i, ret = 0;
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u64 next_cycle;
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struct kvm_vcpu *rvcpu;
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struct kvm *kvm = vcpu->kvm;
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struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
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switch (cp->a7) {
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case SBI_EXT_0_1_CONSOLE_GETCHAR:
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case SBI_EXT_0_1_CONSOLE_PUTCHAR:
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/*
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* The CONSOLE_GETCHAR/CONSOLE_PUTCHAR SBI calls cannot be
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* handled in kernel so we forward these to user-space
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*/
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kvm_riscv_vcpu_sbi_forward(vcpu, run);
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*exit = true;
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break;
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case SBI_EXT_0_1_SET_TIMER:
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#if __riscv_xlen == 32
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next_cycle = ((u64)cp->a1 << 32) | (u64)cp->a0;
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#else
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next_cycle = (u64)cp->a0;
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#endif
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ret = kvm_riscv_vcpu_timer_next_event(vcpu, next_cycle);
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break;
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case SBI_EXT_0_1_CLEAR_IPI:
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ret = kvm_riscv_vcpu_unset_interrupt(vcpu, IRQ_VS_SOFT);
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break;
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case SBI_EXT_0_1_SEND_IPI:
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if (cp->a0)
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hmask = kvm_riscv_vcpu_unpriv_read(vcpu, false, cp->a0,
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utrap);
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else
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hmask = (1UL << atomic_read(&kvm->online_vcpus)) - 1;
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if (utrap->scause)
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break;
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for_each_set_bit(i, &hmask, BITS_PER_LONG) {
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rvcpu = kvm_get_vcpu_by_id(vcpu->kvm, i);
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ret = kvm_riscv_vcpu_set_interrupt(rvcpu, IRQ_VS_SOFT);
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if (ret < 0)
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break;
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}
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break;
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case SBI_EXT_0_1_SHUTDOWN:
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kvm_riscv_vcpu_sbi_system_reset(vcpu, run,
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KVM_SYSTEM_EVENT_SHUTDOWN, 0);
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*exit = true;
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break;
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case SBI_EXT_0_1_REMOTE_FENCE_I:
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case SBI_EXT_0_1_REMOTE_SFENCE_VMA:
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case SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID:
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if (cp->a0)
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hmask = kvm_riscv_vcpu_unpriv_read(vcpu, false, cp->a0,
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utrap);
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else
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hmask = (1UL << atomic_read(&kvm->online_vcpus)) - 1;
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if (utrap->scause)
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break;
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if (cp->a7 == SBI_EXT_0_1_REMOTE_FENCE_I)
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kvm_riscv_fence_i(vcpu->kvm, 0, hmask);
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else if (cp->a7 == SBI_EXT_0_1_REMOTE_SFENCE_VMA) {
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if (cp->a1 == 0 && cp->a2 == 0)
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kvm_riscv_hfence_vvma_all(vcpu->kvm,
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0, hmask);
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else
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kvm_riscv_hfence_vvma_gva(vcpu->kvm,
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0, hmask,
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cp->a1, cp->a2,
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PAGE_SHIFT);
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} else {
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if (cp->a1 == 0 && cp->a2 == 0)
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kvm_riscv_hfence_vvma_asid_all(vcpu->kvm,
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0, hmask,
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cp->a3);
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else
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kvm_riscv_hfence_vvma_asid_gva(vcpu->kvm,
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0, hmask,
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cp->a1, cp->a2,
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PAGE_SHIFT,
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cp->a3);
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}
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break;
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default:
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ret = -EINVAL;
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break;
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}
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return ret;
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}
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const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01 = {
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.extid_start = SBI_EXT_0_1_SET_TIMER,
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.extid_end = SBI_EXT_0_1_SHUTDOWN,
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.handler = kvm_sbi_ext_v01_handler,
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};
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