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Native IPI is used for AP booting, because it is the booting interface
between OS and BIOS firmware. The paravirt IPI is only used inside OS,
and native IPI is necessary to boot AP.
When booting AP, we write the kernel entry address in the HW mailbox of
AP and send IPI interrupt to it. AP executes idle instruction and waits
for interrupts or SW events, then clears IPI interrupt and jumps to the
kernel entry from HW mailbox.
Between writing HW mailbox and sending IPI, AP can be woken up by SW
events and jumps to the kernel entry, so ACTION_BOOT_CPU IPI interrupt
will keep pending during AP booting. And native IPI interrupt handler
needs be registered so that it can clear pending native IPI, else there
will be endless interrupts during AP booting stage.
Here native IPI interrupt is initialized even if paravirt IPI is used.
Cc: stable@vger.kernel.org
Fixes: 74c16b2e2b0c ("LoongArch: KVM: Add PV IPI support on guest side")
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq updates from Thomas Gleixner:
"Core:
- Remove a global lock in the affinity setting code
The lock protects a cpumask for intermediate results and the lock
causes a bottleneck on simultaneous start of multiple virtual
machines. Replace the lock and the static cpumask with a per CPU
cpumask which is nicely serialized by raw spinlock held when
executing this code.
- Provide support for giving a suffix to interrupt domain names.
That's required to support devices with subfunctions so that the
domain names are distinct even if they originate from the same
device node.
- The usual set of cleanups and enhancements all over the place
Drivers:
- Support for longarch AVEC interrupt chip
- Refurbishment of the Armada driver so it can be extended for new
variants.
- The usual set of cleanups and enhancements all over the place"
* tag 'irq-core-2024-09-16' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (73 commits)
genirq: Use cpumask_intersects()
genirq/cpuhotplug: Use cpumask_intersects()
irqchip/apple-aic: Only access system registers on SoCs which provide them
irqchip/apple-aic: Add a new "Global fast IPIs only" feature level
irqchip/apple-aic: Skip unnecessary enabling of use_fast_ipi
dt-bindings: apple,aic: Document A7-A11 compatibles
irqdomain: Use IS_ERR_OR_NULL() in irq_domain_trim_hierarchy()
genirq/msi: Use kmemdup_array() instead of kmemdup()
genirq/proc: Change the return value for set affinity permission error
genirq/proc: Use irq_move_pending() in show_irq_affinity()
genirq/proc: Correctly set file permissions for affinity control files
genirq: Get rid of global lock in irq_do_set_affinity()
genirq: Fix typo in struct comment
irqchip/loongarch-avec: Add AVEC irqchip support
irqchip/loongson-pch-msi: Prepare get_pch_msi_handle() for AVECINTC
irqchip/loongson-eiointc: Rename CPUHP_AP_IRQ_LOONGARCH_STARTING
LoongArch: Architectural preparation for AVEC irqchip
LoongArch: Move irqchip function prototypes to irq-loongson.h
irqchip/loongson-pch-msi: Switch to MSI parent domains
softirq: Remove unused 'action' parameter from action callback
...
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Implement function kvm_para_has_feature() to detect supported paravirt
features. It can be used by device driver to detect and enable paravirt
features, such as the EIOINTC irqchip driver is able to detect feature
KVM_FEATURE_VIRT_EXTIOI and do some optimization.
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Export kernel paravirt features to user space, so that VMM can control
each single paravirt feature. By default paravirt features will be the
same with kvm supported features if VMM does not set it.
Also a new feature KVM_FEATURE_VIRT_EXTIOI is added which can be set
from user space. This feature indicates that the virt EIOINTC can route
interrupts to 256 vCPUs, rather than 4 vCPUs like with real HW.
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Similar with x86, when VM is detected, revert to a simple test-and-set
lock to avoid the horrors of queue preemption.
Tested on 3C5000 Dual-way machine with 32 cores and 2 numa nodes,
test case is kcbench on kernel mainline 6.10, the detailed command is
"kcbench --src /root/src/linux"
Performance on host machine
kernel compile time performance impact
Original 150.29 seconds
With patch 150.19 seconds almost no impact
Performance on virtual machine:
1. 1 VM with 32 vCPUs and 2 numa node, numa node pinned
kernel compile time performance impact
Original 170.87 seconds
With patch 171.73 seconds almost no impact
2. 2 VMs, each VM with 32 vCPUs and 2 numa node, numa node pinned
kernel compile time performance impact
Original 2362.04 seconds
With patch 354.73 seconds +565%
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Introduce the advanced extended interrupt controllers (AVECINTC). This
feature will allow each core to have 256 independent interrupt vectors
and MSI interrupts can be independently routed to any vector on any CPU.
The whole topology of irqchips in LoongArch machines looks like this if
AVECINTC is supported:
+-----+ +-----------------------+ +-------+
| IPI | --> | CPUINTC | <-- | Timer |
+-----+ +-----------------------+ +-------+
^ ^ ^
| | |
+---------+ +----------+ +---------+ +-------+
| EIOINTC | | AVECINTC | | LIOINTC | <-- | UARTs |
+---------+ +----------+ +---------+ +-------+
^ ^
| |
+---------+ +---------+
| PCH-PIC | | PCH-MSI |
+---------+ +---------+
^ ^ ^
| | |
+---------+ +---------+ +---------+
| Devices | | PCH-LPC | | Devices |
+---------+ +---------+ +---------+
^
|
+---------+
| Devices |
+---------+
Co-developed-by: Jianmin Lv <lvjianmin@loongson.cn>
Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
Co-developed-by: Liupu Wang <wangliupu@loongson.cn>
Signed-off-by: Liupu Wang <wangliupu@loongson.cn>
Co-developed-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Tianyang Zhang <zhangtianyang@loongson.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240823104337.25577-2-zhangtianyang@loongson.cn
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git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
Pull LoongArch updates from Huacai Chen:
- Define __ARCH_WANT_NEW_STAT in unistd.h
- Always enumerate MADT and setup logical-physical CPU mapping
- Add irq_work support via self IPIs
- Add RANDOMIZE_KSTACK_OFFSET support
- Add ARCH_HAS_PTE_DEVMAP support
- Add ARCH_HAS_DEBUG_VM_PGTABLE support
- Add writecombine support for DMW-based ioremap()
- Add architectural preparation for CPUFreq
- Add ACPI standard hardware register based S3 support
- Add support for relocating the kernel with RELR relocation
- Some bug fixes and other small changes
* tag 'loongarch-6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
LoongArch: Make the users of larch_insn_gen_break() constant
LoongArch: Check TIF_LOAD_WATCH to enable user space watchpoint
LoongArch: Use rustc option -Zdirect-access-external-data
LoongArch: Add support for relocating the kernel with RELR relocation
LoongArch: Remove a redundant checking in relocator
LoongArch: Use correct API to map cmdline in relocate_kernel()
LoongArch: Automatically disable KASLR for hibernation
LoongArch: Add ACPI standard hardware register based S3 support
LoongArch: Add architectural preparation for CPUFreq
LoongArch: Add writecombine support for DMW-based ioremap()
LoongArch: Add ARCH_HAS_DEBUG_VM_PGTABLE support
LoongArch: Add ARCH_HAS_PTE_DEVMAP support
LoongArch: Add RANDOMIZE_KSTACK_OFFSET support
LoongArch: Add irq_work support via self IPIs
LoongArch: Always enumerate MADT and setup logical-physical CPU mapping
LoongArch: Define __ARCH_WANT_NEW_STAT in unistd.h
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Add irq_work support for LoongArch via self IPIs. This make it possible
to run works in hardware interrupt context, which is a prerequisite for
NOHZ_FULL.
Implement:
- arch_irq_work_raise()
- arch_irq_work_has_interrupt()
Reviewed-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Per-cpu struct kvm_steal_time is added here, its size is 64 bytes and
also defined as 64 bytes, so that the whole structure is in one physical
page.
When a VCPU is online, function pv_enable_steal_time() is called. This
function will pass guest physical address of struct kvm_steal_time and
tells hypervisor to enable steal time. When a vcpu is offline, physical
address is set as 0 and tells hypervisor to disable steal time.
Here is an output of vmstat on guest when there is workload on both host
and guest. It shows steal time stat information.
procs -----------memory---------- -----io---- -system-- ------cpu-----
r b swpd free inact active bi bo in cs us sy id wa st
15 1 0 7583616 184112 72208 20 0 162 52 31 6 43 0 20
17 0 0 7583616 184704 72192 0 0 6318 6885 5 60 8 5 22
16 0 0 7583616 185392 72144 0 0 1766 1081 0 49 0 1 50
16 0 0 7583616 184816 72304 0 0 6300 6166 4 62 12 2 20
18 0 0 7583632 184480 72240 0 0 2814 1754 2 58 4 1 35
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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PARAVIRT config option and PV IPI is added for the guest side, function
pv_ipi_init() is used to add IPI sending and IPI receiving hooks. This
function firstly checks whether system runs in VM mode, and if kernel
runs in VM mode, it will call function kvm_para_available() to detect
the current hypervirsor type (now only KVM type detection is supported).
The paravirt functions can work only if current hypervisor type is KVM,
since there is only KVM supported on LoongArch now.
PV IPI uses virtual IPI sender and virtual IPI receiver functions. With
virtual IPI sender, IPI message is stored in memory rather than emulated
HW. IPI multicast is also supported, and 128 vcpus can received IPIs
at the same time like X86 KVM method. Hypercall method is used for IPI
sending.
With virtual IPI receiver, HW SWI0 is used rather than real IPI HW.
Since VCPU has separate HW SWI0 like HW timer, there is no trap in IPI
interrupt acknowledge. Since IPI message is stored in memory, there is
no trap in getting IPI message.
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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