mirror of
https://github.com/Fishwaldo/linux-bl808.git
synced 2025-06-17 20:25:19 +00:00
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>
124 lines
3.1 KiB
C
124 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Copyright (C) 2019 Western Digital Corporation or its affiliates.
|
|
*
|
|
* Authors:
|
|
* Anup Patel <anup.patel@wdc.com>
|
|
*/
|
|
|
|
#include <linux/bitops.h>
|
|
#include <linux/cpumask.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/err.h>
|
|
#include <linux/module.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/kvm_host.h>
|
|
#include <asm/csr.h>
|
|
|
|
static unsigned long vmid_version = 1;
|
|
static unsigned long vmid_next;
|
|
static unsigned long vmid_bits;
|
|
static DEFINE_SPINLOCK(vmid_lock);
|
|
|
|
void kvm_riscv_gstage_vmid_detect(void)
|
|
{
|
|
unsigned long old;
|
|
|
|
/* Figure-out number of VMID bits in HW */
|
|
old = csr_read(CSR_HGATP);
|
|
csr_write(CSR_HGATP, old | HGATP_VMID_MASK);
|
|
vmid_bits = csr_read(CSR_HGATP);
|
|
vmid_bits = (vmid_bits & HGATP_VMID_MASK) >> HGATP_VMID_SHIFT;
|
|
vmid_bits = fls_long(vmid_bits);
|
|
csr_write(CSR_HGATP, old);
|
|
|
|
/* We polluted local TLB so flush all guest TLB */
|
|
kvm_riscv_local_hfence_gvma_all();
|
|
|
|
/* We don't use VMID bits if they are not sufficient */
|
|
if ((1UL << vmid_bits) < num_possible_cpus())
|
|
vmid_bits = 0;
|
|
}
|
|
|
|
unsigned long kvm_riscv_gstage_vmid_bits(void)
|
|
{
|
|
return vmid_bits;
|
|
}
|
|
|
|
int kvm_riscv_gstage_vmid_init(struct kvm *kvm)
|
|
{
|
|
/* Mark the initial VMID and VMID version invalid */
|
|
kvm->arch.vmid.vmid_version = 0;
|
|
kvm->arch.vmid.vmid = 0;
|
|
|
|
return 0;
|
|
}
|
|
|
|
bool kvm_riscv_gstage_vmid_ver_changed(struct kvm_vmid *vmid)
|
|
{
|
|
if (!vmid_bits)
|
|
return false;
|
|
|
|
return unlikely(READ_ONCE(vmid->vmid_version) !=
|
|
READ_ONCE(vmid_version));
|
|
}
|
|
|
|
static void __local_hfence_gvma_all(void *info)
|
|
{
|
|
kvm_riscv_local_hfence_gvma_all();
|
|
}
|
|
|
|
void kvm_riscv_gstage_vmid_update(struct kvm_vcpu *vcpu)
|
|
{
|
|
unsigned long i;
|
|
struct kvm_vcpu *v;
|
|
struct kvm_vmid *vmid = &vcpu->kvm->arch.vmid;
|
|
|
|
if (!kvm_riscv_gstage_vmid_ver_changed(vmid))
|
|
return;
|
|
|
|
spin_lock(&vmid_lock);
|
|
|
|
/*
|
|
* We need to re-check the vmid_version here to ensure that if
|
|
* another vcpu already allocated a valid vmid for this vm.
|
|
*/
|
|
if (!kvm_riscv_gstage_vmid_ver_changed(vmid)) {
|
|
spin_unlock(&vmid_lock);
|
|
return;
|
|
}
|
|
|
|
/* First user of a new VMID version? */
|
|
if (unlikely(vmid_next == 0)) {
|
|
WRITE_ONCE(vmid_version, READ_ONCE(vmid_version) + 1);
|
|
vmid_next = 1;
|
|
|
|
/*
|
|
* We ran out of VMIDs so we increment vmid_version and
|
|
* start assigning VMIDs from 1.
|
|
*
|
|
* This also means existing VMIDs assignement to all Guest
|
|
* instances is invalid and we have force VMID re-assignement
|
|
* for all Guest instances. The Guest instances that were not
|
|
* running will automatically pick-up new VMIDs because will
|
|
* call kvm_riscv_gstage_vmid_update() whenever they enter
|
|
* in-kernel run loop. For Guest instances that are already
|
|
* running, we force VM exits on all host CPUs using IPI and
|
|
* flush all Guest TLBs.
|
|
*/
|
|
on_each_cpu_mask(cpu_online_mask, __local_hfence_gvma_all,
|
|
NULL, 1);
|
|
}
|
|
|
|
vmid->vmid = vmid_next;
|
|
vmid_next++;
|
|
vmid_next &= (1 << vmid_bits) - 1;
|
|
|
|
WRITE_ONCE(vmid->vmid_version, READ_ONCE(vmid_version));
|
|
|
|
spin_unlock(&vmid_lock);
|
|
|
|
/* Request G-stage page table update for all VCPUs */
|
|
kvm_for_each_vcpu(i, v, vcpu->kvm)
|
|
kvm_make_request(KVM_REQ_UPDATE_HGATP, v);
|
|
}
|