Para-virt feature steal time is added in both kvm and guest kernel side.
It is silimar with other architectures, steal time structure comes from
guest memory, also pseduo register is used to save/restore base address
of steal time structure, so that when vm is migrated, kvm module on
target machine knows the base address of steal time.
---
v3 ... v4:
1. To resolve compile dependency problem, enable SCHED_INFO option
section if KVM is enabled.
2. Put new added option PARAVIRT_TIME_ACCOUNTING in one submemu with
PARAVIRT in file arch/loongarch/Kconfig.
v2 ... v3:
1. Solve code confliction based on the kernel 6.9.0
2. Add kernel parameter no-steal-acc support on LoongArch with file
Documentation/admin-guide/kernel-parameters.txt
3. Add strict checking with pv stealtimer gpa address in function
kvm_save_notify() and kvm_loongarch_pvtime_set_attr()
v1 ... v2:
1. Add PARAVIRT_TIME_ACCOUNTING kconfig option in file
arch/loongarch/Kconfig
2. Function name change such as replace pv_register_steal_time with
pv_enable_steal_time etc
---
Bibo Mao (2):
LoongArch: KVM: Add steal time support in kvm side
LoongArch: Add steal time support in guest side
.../admin-guide/kernel-parameters.txt | 2 +-
arch/loongarch/Kconfig | 11 ++
arch/loongarch/include/asm/kvm_host.h | 7 +
arch/loongarch/include/asm/kvm_para.h | 10 ++
arch/loongarch/include/asm/kvm_vcpu.h | 4 +
arch/loongarch/include/asm/loongarch.h | 1 +
arch/loongarch/include/asm/paravirt.h | 5 +
arch/loongarch/include/uapi/asm/kvm.h | 4 +
arch/loongarch/kernel/paravirt.c | 133 ++++++++++++++++++
arch/loongarch/kernel/time.c | 2 +
arch/loongarch/kvm/Kconfig | 1 +
arch/loongarch/kvm/exit.c | 38 ++++-
arch/loongarch/kvm/vcpu.c | 124 ++++++++++++++++
13 files changed, 339 insertions(+), 3 deletions(-)
base-commit: 6e51b4b5bbc07e52b226017936874715629932d1
--
2.39.3
Steal time feature is added here in kvm side, VM can search supported
features provided by KVM hypervisor, feature KVM_FEATURE_STEAL_TIME
is added here. Like x86, steal time structure is saved in guest memory,
one hypercall function KVM_HCALL_FUNC_NOTIFY is added to notify KVM to
enable the feature.
One cpu attr ioctl command KVM_LOONGARCH_VCPU_PVTIME_CTRL is added to
save and restore base address of steal time structure when VM is migrated.
Signed-off-by: Bibo Mao <[email protected]>
---
arch/loongarch/include/asm/kvm_host.h | 7 ++
arch/loongarch/include/asm/kvm_para.h | 10 ++
arch/loongarch/include/asm/kvm_vcpu.h | 4 +
arch/loongarch/include/asm/loongarch.h | 1 +
arch/loongarch/include/uapi/asm/kvm.h | 4 +
arch/loongarch/kvm/Kconfig | 1 +
arch/loongarch/kvm/exit.c | 38 +++++++-
arch/loongarch/kvm/vcpu.c | 124 +++++++++++++++++++++++++
8 files changed, 187 insertions(+), 2 deletions(-)
diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h
index c87b6ea0ec47..2eb2f7572023 100644
--- a/arch/loongarch/include/asm/kvm_host.h
+++ b/arch/loongarch/include/asm/kvm_host.h
@@ -30,6 +30,7 @@
#define KVM_PRIVATE_MEM_SLOTS 0
#define KVM_HALT_POLL_NS_DEFAULT 500000
+#define KVM_REQ_STEAL_UPDATE KVM_ARCH_REQ(1)
#define KVM_GUESTDBG_SW_BP_MASK \
(KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP)
@@ -201,6 +202,12 @@ struct kvm_vcpu_arch {
struct kvm_mp_state mp_state;
/* cpucfg */
u32 cpucfg[KVM_MAX_CPUCFG_REGS];
+ /* paravirt steal time */
+ struct {
+ u64 guest_addr;
+ u64 last_steal;
+ struct gfn_to_hva_cache cache;
+ } st;
};
static inline unsigned long readl_sw_gcsr(struct loongarch_csrs *csr, int reg)
diff --git a/arch/loongarch/include/asm/kvm_para.h b/arch/loongarch/include/asm/kvm_para.h
index 4ba2312e5f8c..a9ba8185d4af 100644
--- a/arch/loongarch/include/asm/kvm_para.h
+++ b/arch/loongarch/include/asm/kvm_para.h
@@ -14,6 +14,7 @@
#define KVM_HCALL_SERVICE HYPERCALL_ENCODE(HYPERVISOR_KVM, KVM_HCALL_CODE_SERVICE)
#define KVM_HCALL_FUNC_IPI 1
+#define KVM_HCALL_FUNC_NOTIFY 2
#define KVM_HCALL_SWDBG HYPERCALL_ENCODE(HYPERVISOR_KVM, KVM_HCALL_CODE_SWDBG)
@@ -24,6 +25,15 @@
#define KVM_HCALL_INVALID_CODE -1UL
#define KVM_HCALL_INVALID_PARAMETER -2UL
+#define KVM_STEAL_PHYS_VALID BIT_ULL(0)
+#define KVM_STEAL_PHYS_MASK GENMASK_ULL(63, 6)
+struct kvm_steal_time {
+ __u64 steal;
+ __u32 version;
+ __u32 flags;
+ __u32 pad[12];
+};
+
/*
* Hypercall interface for KVM hypervisor
*
diff --git a/arch/loongarch/include/asm/kvm_vcpu.h b/arch/loongarch/include/asm/kvm_vcpu.h
index 590a92cb5416..d7e51300a89f 100644
--- a/arch/loongarch/include/asm/kvm_vcpu.h
+++ b/arch/loongarch/include/asm/kvm_vcpu.h
@@ -120,4 +120,8 @@ static inline void kvm_write_reg(struct kvm_vcpu *vcpu, int num, unsigned long v
vcpu->arch.gprs[num] = val;
}
+static inline bool kvm_pvtime_supported(void)
+{
+ return !!sched_info_on();
+}
#endif /* __ASM_LOONGARCH_KVM_VCPU_H__ */
diff --git a/arch/loongarch/include/asm/loongarch.h b/arch/loongarch/include/asm/loongarch.h
index eb09adda54b7..7a4633ef284b 100644
--- a/arch/loongarch/include/asm/loongarch.h
+++ b/arch/loongarch/include/asm/loongarch.h
@@ -169,6 +169,7 @@
#define KVM_SIGNATURE "KVM\0"
#define CPUCFG_KVM_FEATURE (CPUCFG_KVM_BASE + 4)
#define KVM_FEATURE_IPI BIT(1)
+#define KVM_FEATURE_STEAL_TIME BIT(2)
#ifndef __ASSEMBLY__
diff --git a/arch/loongarch/include/uapi/asm/kvm.h b/arch/loongarch/include/uapi/asm/kvm.h
index f9abef382317..ddc5cab0ffd0 100644
--- a/arch/loongarch/include/uapi/asm/kvm.h
+++ b/arch/loongarch/include/uapi/asm/kvm.h
@@ -81,7 +81,11 @@ struct kvm_fpu {
#define LOONGARCH_REG_64(TYPE, REG) (TYPE | KVM_REG_SIZE_U64 | (REG << LOONGARCH_REG_SHIFT))
#define KVM_IOC_CSRID(REG) LOONGARCH_REG_64(KVM_REG_LOONGARCH_CSR, REG)
#define KVM_IOC_CPUCFG(REG) LOONGARCH_REG_64(KVM_REG_LOONGARCH_CPUCFG, REG)
+
+/* Device Control API on vcpu fd */
#define KVM_LOONGARCH_VCPU_CPUCFG 0
+#define KVM_LOONGARCH_VCPU_PVTIME_CTRL 1
+#define KVM_LOONGARCH_VCPU_PVTIME_GPA 0
struct kvm_debug_exit_arch {
};
diff --git a/arch/loongarch/kvm/Kconfig b/arch/loongarch/kvm/Kconfig
index c4ef2b4d9797..248744b4d086 100644
--- a/arch/loongarch/kvm/Kconfig
+++ b/arch/loongarch/kvm/Kconfig
@@ -29,6 +29,7 @@ config KVM
select KVM_MMIO
select HAVE_KVM_READONLY_MEM
select KVM_XFER_TO_GUEST_WORK
+ select SCHED_INFO
help
Support hosting virtualized guest machines using
hardware virtualization extensions. You will need
diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c
index c86e099af5ca..e2abd97fb13f 100644
--- a/arch/loongarch/kvm/exit.c
+++ b/arch/loongarch/kvm/exit.c
@@ -24,7 +24,7 @@
static int kvm_emu_cpucfg(struct kvm_vcpu *vcpu, larch_inst inst)
{
int rd, rj;
- unsigned int index;
+ unsigned int index, ret;
if (inst.reg2_format.opcode != cpucfg_op)
return EMULATE_FAIL;
@@ -50,7 +50,10 @@ static int kvm_emu_cpucfg(struct kvm_vcpu *vcpu, larch_inst inst)
vcpu->arch.gprs[rd] = *(unsigned int *)KVM_SIGNATURE;
break;
case CPUCFG_KVM_FEATURE:
- vcpu->arch.gprs[rd] = KVM_FEATURE_IPI;
+ ret = KVM_FEATURE_IPI;
+ if (sched_info_on())
+ ret |= KVM_FEATURE_STEAL_TIME;
+ vcpu->arch.gprs[rd] = ret;
break;
default:
vcpu->arch.gprs[rd] = 0;
@@ -687,6 +690,34 @@ static int kvm_handle_fpu_disabled(struct kvm_vcpu *vcpu)
return RESUME_GUEST;
}
+static long kvm_save_notify(struct kvm_vcpu *vcpu)
+{
+ unsigned long id, data;
+
+ id = kvm_read_reg(vcpu, LOONGARCH_GPR_A1);
+ data = kvm_read_reg(vcpu, LOONGARCH_GPR_A2);
+ switch (id) {
+ case KVM_FEATURE_STEAL_TIME:
+ if (!kvm_pvtime_supported())
+ return KVM_HCALL_INVALID_CODE;
+
+ if (data & ~(KVM_STEAL_PHYS_MASK | KVM_STEAL_PHYS_VALID))
+ return KVM_HCALL_INVALID_PARAMETER;
+
+ vcpu->arch.st.guest_addr = data;
+ if (!(data & KVM_STEAL_PHYS_VALID))
+ break;
+
+ vcpu->arch.st.last_steal = current->sched_info.run_delay;
+ kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu);
+ break;
+ default:
+ break;
+ };
+
+ return 0;
+};
+
/*
* kvm_handle_lsx_disabled() - Guest used LSX while disabled in root.
* @vcpu: Virtual CPU context.
@@ -758,6 +789,9 @@ static void kvm_handle_service(struct kvm_vcpu *vcpu)
kvm_send_pv_ipi(vcpu);
ret = KVM_HCALL_SUCCESS;
break;
+ case KVM_HCALL_FUNC_NOTIFY:
+ ret = kvm_save_notify(vcpu);
+ break;
default:
ret = KVM_HCALL_INVALID_CODE;
break;
diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index 9e8030d45129..382796f1d3e6 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -31,6 +31,117 @@ const struct kvm_stats_header kvm_vcpu_stats_header = {
sizeof(kvm_vcpu_stats_desc),
};
+static void kvm_update_stolen_time(struct kvm_vcpu *vcpu)
+{
+ struct kvm_steal_time __user *st;
+ struct gfn_to_hva_cache *ghc;
+ struct kvm_memslots *slots;
+ gpa_t gpa;
+ u64 steal;
+ u32 version;
+
+ ghc = &vcpu->arch.st.cache;
+ gpa = vcpu->arch.st.guest_addr;
+ if (!(gpa & KVM_STEAL_PHYS_VALID))
+ return;
+
+ gpa &= KVM_STEAL_PHYS_MASK;
+ slots = kvm_memslots(vcpu->kvm);
+ if (slots->generation != ghc->generation || gpa != ghc->gpa) {
+ if (kvm_gfn_to_hva_cache_init(vcpu->kvm, ghc, gpa,
+ sizeof(*st))) {
+ ghc->gpa = INVALID_GPA;
+ return;
+ }
+ }
+
+ st = (struct kvm_steal_time __user *)ghc->hva;
+ unsafe_get_user(version, &st->version, out);
+ if (version & 1)
+ version += 1;
+ version += 1;
+ unsafe_put_user(version, &st->version, out);
+ smp_wmb();
+
+ unsafe_get_user(steal, &st->steal, out);
+ steal += current->sched_info.run_delay -
+ vcpu->arch.st.last_steal;
+ vcpu->arch.st.last_steal = current->sched_info.run_delay;
+ unsafe_put_user(steal, &st->steal, out);
+
+ smp_wmb();
+ version += 1;
+ unsafe_put_user(version, &st->version, out);
+out:
+ mark_page_dirty_in_slot(vcpu->kvm, ghc->memslot, gpa_to_gfn(ghc->gpa));
+}
+
+static int kvm_loongarch_pvtime_has_attr(struct kvm_vcpu *vcpu,
+ struct kvm_device_attr *attr)
+{
+ if (!kvm_pvtime_supported() ||
+ attr->attr != KVM_LOONGARCH_VCPU_PVTIME_GPA)
+ return -ENXIO;
+
+ return 0;
+}
+
+static int kvm_loongarch_pvtime_get_attr(struct kvm_vcpu *vcpu,
+ struct kvm_device_attr *attr)
+{
+ u64 __user *user = (u64 __user *)attr->addr;
+ u64 gpa;
+
+ if (!kvm_pvtime_supported() ||
+ attr->attr != KVM_LOONGARCH_VCPU_PVTIME_GPA)
+ return -ENXIO;
+
+ gpa = vcpu->arch.st.guest_addr;
+ if (put_user(gpa, user))
+ return -EFAULT;
+
+ return 0;
+}
+
+static int kvm_loongarch_pvtime_set_attr(struct kvm_vcpu *vcpu,
+ struct kvm_device_attr *attr)
+{
+ u64 __user *user = (u64 __user *)attr->addr;
+ struct kvm *kvm = vcpu->kvm;
+ u64 gpa;
+ int ret = 0;
+ int idx;
+
+ if (!kvm_pvtime_supported() ||
+ attr->attr != KVM_LOONGARCH_VCPU_PVTIME_GPA)
+ return -ENXIO;
+
+ if (get_user(gpa, user))
+ return -EFAULT;
+
+ if (gpa & ~(KVM_STEAL_PHYS_MASK | KVM_STEAL_PHYS_VALID))
+ return -EINVAL;
+
+ if (!(gpa & KVM_STEAL_PHYS_VALID)) {
+ vcpu->arch.st.guest_addr = gpa;
+ return 0;
+ }
+
+ /* Check the address is in a valid memslot */
+ idx = srcu_read_lock(&kvm->srcu);
+ if (kvm_is_error_hva(gfn_to_hva(kvm, gpa >> PAGE_SHIFT)))
+ ret = -EINVAL;
+ srcu_read_unlock(&kvm->srcu, idx);
+
+ if (!ret) {
+ vcpu->arch.st.guest_addr = gpa;
+ vcpu->arch.st.last_steal = current->sched_info.run_delay;
+ kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu);
+ }
+
+ return ret;
+}
+
/*
* kvm_check_requests - check and handle pending vCPU requests
*
@@ -48,6 +159,9 @@ static int kvm_check_requests(struct kvm_vcpu *vcpu)
if (kvm_dirty_ring_check_request(vcpu))
return RESUME_HOST;
+ if (kvm_check_request(KVM_REQ_STEAL_UPDATE, vcpu))
+ kvm_update_stolen_time(vcpu);
+
return RESUME_GUEST;
}
@@ -671,6 +785,9 @@ static int kvm_loongarch_vcpu_has_attr(struct kvm_vcpu *vcpu,
case KVM_LOONGARCH_VCPU_CPUCFG:
ret = kvm_loongarch_cpucfg_has_attr(vcpu, attr);
break;
+ case KVM_LOONGARCH_VCPU_PVTIME_CTRL:
+ ret = kvm_loongarch_pvtime_has_attr(vcpu, attr);
+ break;
default:
break;
}
@@ -703,6 +820,9 @@ static int kvm_loongarch_vcpu_get_attr(struct kvm_vcpu *vcpu,
case KVM_LOONGARCH_VCPU_CPUCFG:
ret = kvm_loongarch_get_cpucfg_attr(vcpu, attr);
break;
+ case KVM_LOONGARCH_VCPU_PVTIME_CTRL:
+ ret = kvm_loongarch_pvtime_get_attr(vcpu, attr);
+ break;
default:
break;
}
@@ -725,6 +845,9 @@ static int kvm_loongarch_vcpu_set_attr(struct kvm_vcpu *vcpu,
case KVM_LOONGARCH_VCPU_CPUCFG:
ret = kvm_loongarch_cpucfg_set_attr(vcpu, attr);
break;
+ case KVM_LOONGARCH_VCPU_PVTIME_CTRL:
+ ret = kvm_loongarch_pvtime_set_attr(vcpu, attr);
+ break;
default:
break;
}
@@ -1084,6 +1207,7 @@ static int _kvm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
/* Control guest page CCA attribute */
change_csr_gcfg(CSR_GCFG_MATC_MASK, CSR_GCFG_MATC_ROOT);
+ kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu);
/* Don't bother restoring registers multiple times unless necessary */
if (vcpu->arch.aux_inuse & KVM_LARCH_HWCSR_USABLE)
--
2.39.3