Re: [PATCH v3 5/6] LoongArch: KVM: Add physical cpuid map support
From: maobibo
Date: Mon Jan 29 2024 - 21:53:52 EST
On 2024/1/29 下午9:11, Huacai Chen wrote:
Hi, Bibo,
Without this patch I can also create a SMP VM, so what problem does
this patch want to solve?
With ipi irqchip, physical cpuid is used for dest cpu rather than
logical cpuid. And if ipi device is emulated in qemu side, there is
find_cpu_by_archid to get dest vcpu in file hw/intc/loongarch_ipi.c
Here with hypercall method, ipi is emulated in kvm kernel side, there
should be the same physical cpuid searching logic. And function
kvm_get_vcpu_by_cpuid is used with pv_ipi backend.
Regards
Bibo Mao
Huacai
On Mon, Jan 22, 2024 at 6:03 PM Bibo Mao <maobibo@xxxxxxxxxxx> wrote:
Physical cpuid is used to irq routing for irqchips such as ipi/msi/
extioi interrupt controller. And physical cpuid is stored at CSR
register LOONGARCH_CSR_CPUID, it can not be changed once vcpu is
created. Since different irqchips have different size definition
about physical cpuid, KVM uses the smallest cpuid from extioi, and
the max cpuid size is defines as 256.
Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
---
arch/loongarch/include/asm/kvm_host.h | 26 ++++++++
arch/loongarch/include/asm/kvm_vcpu.h | 1 +
arch/loongarch/kvm/vcpu.c | 93 ++++++++++++++++++++++++++-
arch/loongarch/kvm/vm.c | 11 ++++
4 files changed, 130 insertions(+), 1 deletion(-)
diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h
index 2d62f7b0d377..57399d7cf8b7 100644
--- a/arch/loongarch/include/asm/kvm_host.h
+++ b/arch/loongarch/include/asm/kvm_host.h
@@ -64,6 +64,30 @@ struct kvm_world_switch {
#define MAX_PGTABLE_LEVELS 4
+/*
+ * Physical cpu id is used for interrupt routing, there are different
+ * definitions about physical cpuid on different hardwares.
+ * For LOONGARCH_CSR_CPUID register, max cpuid size if 512
+ * For IPI HW, max dest CPUID size 1024
+ * For extioi interrupt controller, max dest CPUID size is 256
+ * For MSI interrupt controller, max supported CPUID size is 65536
+ *
+ * Currently max CPUID is defined as 256 for KVM hypervisor, in future
+ * it will be expanded to 4096, including 16 packages at most. And every
+ * package supports at most 256 vcpus
+ */
+#define KVM_MAX_PHYID 256
+
+struct kvm_phyid_info {
+ struct kvm_vcpu *vcpu;
+ bool enabled;
+};
+
+struct kvm_phyid_map {
+ int max_phyid;
+ struct kvm_phyid_info phys_map[KVM_MAX_PHYID];
+};
+
struct kvm_arch {
/* Guest physical mm */
kvm_pte_t *pgd;
@@ -71,6 +95,8 @@ struct kvm_arch {
unsigned long invalid_ptes[MAX_PGTABLE_LEVELS];
unsigned int pte_shifts[MAX_PGTABLE_LEVELS];
unsigned int root_level;
+ struct mutex phyid_map_lock;
+ struct kvm_phyid_map *phyid_map;
s64 time_offset;
struct kvm_context __percpu *vmcs;
diff --git a/arch/loongarch/include/asm/kvm_vcpu.h b/arch/loongarch/include/asm/kvm_vcpu.h
index e71ceb88f29e..2402129ee955 100644
--- a/arch/loongarch/include/asm/kvm_vcpu.h
+++ b/arch/loongarch/include/asm/kvm_vcpu.h
@@ -81,6 +81,7 @@ void kvm_save_timer(struct kvm_vcpu *vcpu);
void kvm_restore_timer(struct kvm_vcpu *vcpu);
int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu, struct kvm_interrupt *irq);
+struct kvm_vcpu *kvm_get_vcpu_by_cpuid(struct kvm *kvm, int cpuid);
/*
* Loongarch KVM guest interrupt handling
diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index 27701991886d..97ca9c7160e6 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -274,6 +274,95 @@ static int _kvm_getcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 *val)
return 0;
}
+static inline int kvm_set_cpuid(struct kvm_vcpu *vcpu, u64 val)
+{
+ int cpuid;
+ struct loongarch_csrs *csr = vcpu->arch.csr;
+ struct kvm_phyid_map *map;
+
+ if (val >= KVM_MAX_PHYID)
+ return -EINVAL;
+
+ cpuid = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_ESTAT);
+ map = vcpu->kvm->arch.phyid_map;
+ mutex_lock(&vcpu->kvm->arch.phyid_map_lock);
+ if (map->phys_map[cpuid].enabled) {
+ /*
+ * Cpuid is already set before
+ * Forbid changing different cpuid at runtime
+ */
+ if (cpuid != val) {
+ /*
+ * Cpuid 0 is initial value for vcpu, maybe invalid
+ * unset value for vcpu
+ */
+ if (cpuid) {
+ mutex_unlock(&vcpu->kvm->arch.phyid_map_lock);
+ return -EINVAL;
+ }
+ } else {
+ /* Discard duplicated cpuid set */
+ mutex_unlock(&vcpu->kvm->arch.phyid_map_lock);
+ return 0;
+ }
+ }
+
+ if (map->phys_map[val].enabled) {
+ /*
+ * New cpuid is already set with other vcpu
+ * Forbid sharing the same cpuid between different vcpus
+ */
+ if (map->phys_map[val].vcpu != vcpu) {
+ mutex_unlock(&vcpu->kvm->arch.phyid_map_lock);
+ return -EINVAL;
+ }
+
+ /* Discard duplicated cpuid set operation*/
+ mutex_unlock(&vcpu->kvm->arch.phyid_map_lock);
+ return 0;
+ }
+
+ kvm_write_sw_gcsr(csr, LOONGARCH_CSR_CPUID, val);
+ map->phys_map[val].enabled = true;
+ map->phys_map[val].vcpu = vcpu;
+ if (map->max_phyid < val)
+ map->max_phyid = val;
+ mutex_unlock(&vcpu->kvm->arch.phyid_map_lock);
+ return 0;
+}
+
+struct kvm_vcpu *kvm_get_vcpu_by_cpuid(struct kvm *kvm, int cpuid)
+{
+ struct kvm_phyid_map *map;
+
+ if (cpuid >= KVM_MAX_PHYID)
+ return NULL;
+
+ map = kvm->arch.phyid_map;
+ if (map->phys_map[cpuid].enabled)
+ return map->phys_map[cpuid].vcpu;
+
+ return NULL;
+}
+
+static inline void kvm_drop_cpuid(struct kvm_vcpu *vcpu)
+{
+ int cpuid;
+ struct loongarch_csrs *csr = vcpu->arch.csr;
+ struct kvm_phyid_map *map;
+
+ map = vcpu->kvm->arch.phyid_map;
+ cpuid = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_ESTAT);
+ if (cpuid >= KVM_MAX_PHYID)
+ return;
+
+ if (map->phys_map[cpuid].enabled) {
+ map->phys_map[cpuid].vcpu = NULL;
+ map->phys_map[cpuid].enabled = false;
+ kvm_write_sw_gcsr(csr, LOONGARCH_CSR_CPUID, 0);
+ }
+}
+
static int _kvm_setcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 val)
{
int ret = 0, gintc;
@@ -291,7 +380,8 @@ static int _kvm_setcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 val)
kvm_set_sw_gcsr(csr, LOONGARCH_CSR_ESTAT, gintc);
return ret;
- }
+ } else if (id == LOONGARCH_CSR_CPUID)
+ return kvm_set_cpuid(vcpu, val);
kvm_write_sw_gcsr(csr, id, val);
@@ -925,6 +1015,7 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
hrtimer_cancel(&vcpu->arch.swtimer);
kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
kfree(vcpu->arch.csr);
+ kvm_drop_cpuid(vcpu);
/*
* If the vCPU is freed and reused as another vCPU, we don't want the
diff --git a/arch/loongarch/kvm/vm.c b/arch/loongarch/kvm/vm.c
index 0a37f6fa8f2d..6fd5916ebef3 100644
--- a/arch/loongarch/kvm/vm.c
+++ b/arch/loongarch/kvm/vm.c
@@ -30,6 +30,14 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
if (!kvm->arch.pgd)
return -ENOMEM;
+ kvm->arch.phyid_map = kvzalloc(sizeof(struct kvm_phyid_map),
+ GFP_KERNEL_ACCOUNT);
+ if (!kvm->arch.phyid_map) {
+ free_page((unsigned long)kvm->arch.pgd);
+ kvm->arch.pgd = NULL;
+ return -ENOMEM;
+ }
+
kvm_init_vmcs(kvm);
kvm->arch.gpa_size = BIT(cpu_vabits - 1);
kvm->arch.root_level = CONFIG_PGTABLE_LEVELS - 1;
@@ -44,6 +52,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
for (i = 0; i <= kvm->arch.root_level; i++)
kvm->arch.pte_shifts[i] = PAGE_SHIFT + i * (PAGE_SHIFT - 3);
+ mutex_init(&kvm->arch.phyid_map_lock);
return 0;
}
@@ -51,7 +60,9 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
{
kvm_destroy_vcpus(kvm);
free_page((unsigned long)kvm->arch.pgd);
+ kvfree(kvm->arch.phyid_map);
kvm->arch.pgd = NULL;
+ kvm->arch.phyid_map = NULL;
}
int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
--
2.39.3