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2025-03-08LoongArch: KVM: Fix GPA size issue about VMBibo Mao
Physical address space is 48 bit on Loongson-3A5000 physical machine, however it is 47 bit for VM on Loongson-3A5000 system. Size of physical address space of VM is the same with the size of virtual user space (a half) of physical machine. Variable cpu_vabits represents user address space, kernel address space is not included (user space and kernel space are both a half of total). Here cpu_vabits, rather than cpu_vabits - 1, is to represent the size of guest physical address space. Also there is strict checking about page fault GPA address, inject error if it is larger than maximum GPA address of VM. Cc: stable@vger.kernel.org Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2025-01-13LoongArch: KVM: Add hypercall service support for usermode VMMBibo Mao
Some VMMs provides special hypercall service in usermode, KVM should not handle the usermode hypercall service, thus pass it to usermode, let the usermode VMM handle it. Here a new code KVM_HCALL_CODE_USER_SERVICE is added for the user-mode hypercall service, KVM lets all six registers visible to usermode VMM. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-12-03LoongArch: KVM: Protect kvm_io_bus_{read,write}() with SRCUHuacai Chen
When we enable lockdep we get such a warning: ============================= WARNING: suspicious RCU usage 6.12.0-rc7+ #1891 Tainted: G W ----------------------------- arch/loongarch/kvm/../../../virt/kvm/kvm_main.c:5945 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by qemu-system-loo/948: #0: 90000001184a00a8 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0xf4/0xe20 [kvm] stack backtrace: CPU: 2 UID: 0 PID: 948 Comm: qemu-system-loo Tainted: G W 6.12.0-rc7+ #1891 Tainted: [W]=WARN Hardware name: Loongson Loongson-3A5000-7A1000-1w-CRB/Loongson-LS3A5000-7A1000-1w-CRB, BIOS vUDK2018-LoongArch-V2.0.0-prebeta9 10/21/2022 Stack : 0000000000000089 9000000005a0db9c 90000000071519c8 900000012c578000 900000012c57b940 0000000000000000 900000012c57b948 9000000007e53788 900000000815bcc8 900000000815bcc0 900000012c57b7b0 0000000000000001 0000000000000001 4b031894b9d6b725 0000000005dec000 9000000100427b00 00000000000003d2 0000000000000001 000000000000002d 0000000000000003 0000000000000030 00000000000003b4 0000000005dec000 0000000000000000 900000000806d000 9000000007e53788 00000000000000b4 0000000000000004 0000000000000004 0000000000000000 0000000000000000 9000000107baf600 9000000008916000 9000000007e53788 9000000005924778 000000001fe001e5 00000000000000b0 0000000000000007 0000000000000000 0000000000071c1d ... Call Trace: [<9000000005924778>] show_stack+0x38/0x180 [<90000000071519c4>] dump_stack_lvl+0x94/0xe4 [<90000000059eb754>] lockdep_rcu_suspicious+0x194/0x240 [<ffff80000221f47c>] kvm_io_bus_read+0x19c/0x1e0 [kvm] [<ffff800002225118>] kvm_emu_mmio_read+0xd8/0x440 [kvm] [<ffff8000022254bc>] kvm_handle_read_fault+0x3c/0xe0 [kvm] [<ffff80000222b3c8>] kvm_handle_exit+0x228/0x480 [kvm] Fix it by protecting kvm_io_bus_{read,write}() with SRCU. Cc: stable@vger.kernel.org Reviewed-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-11-13LoongArch: KVM: Add iocsr and mmio bus simulation in kernelXianglai Li
Add iocsr and mmio memory read and write simulation to the kernel. When the VM accesses the device address space through iocsr instructions or mmio, it does not need to return to the qemu user mode but can directly completes the access in the kernel mode. Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn> Signed-off-by: Xianglai Li <lixianglai@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-09-12LoongArch: KVM: Enable paravirt feature control from VMMBibo Mao
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>
2024-09-12LoongArch: KVM: Add PMU support for guestSong Gao
On LoongArch, the host and guest have their own PMU CSRs registers and they share PMU hardware resources. A set of PMU CSRs consists of a CTRL register and a CNTR register. We can set which PMU CSRs are used by the guest by writing to the GCFG register [24:26] bits. On KVM side: - Save the host PMU CSRs into structure kvm_context. - If the host supports the PMU feature. - When entering guest mode, save the host PMU CSRs and restore the guest PMU CSRs. - When exiting guest mode, save the guest PMU CSRs and restore the host PMU CSRs. Reviewed-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Song Gao <gaosong@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-09-11LoongArch: KVM: Add Binary Translation extension supportBibo Mao
Loongson Binary Translation (LBT) is used to accelerate binary translation, which contains 4 scratch registers (scr0 to scr3), x86/ARM eflags (eflags) and x87 fpu stack pointer (ftop). Like FPU extension, here a lazy enabling method is used for LBT. the LBT context is saved/restored on the vcpu context switch path. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-07-09LoongArch: KVM: Add PV steal time support in host sideBibo Mao
Add ParaVirt steal time feature in host side, VM can search supported features provided by KVM hypervisor, a 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 this feature. One CPU attr ioctl command KVM_LOONGARCH_VCPU_PVTIME_CTRL is added to save and restore the base address of steal time structure when a VM is migrated. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-06-21LoongArch: KVM: Remove an unneeded semicolonYang Li
Remove an unneeded semicolon to avoid build warnings: ./arch/loongarch/kvm/exit.c:764:2-3: Unneeded semicolon Cc: stable@vger.kernel.org Reported-by: Abaci Robot <abaci@linux.alibaba.com> Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=9343 Signed-off-by: Yang Li <yang.lee@linux.alibaba.com> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-05-06LoongArch: KVM: Add mmio trace events supportBibo Mao
Add mmio trace events support, currently generic mmio events KVM_TRACE_MMIO_WRITE/xxx_READ/xx_READ_UNSATISFIED are added here. Also vcpu id field is added for all kvm trace events, since perf KVM tool parses vcpu id information for kvm entry event. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-05-06LoongArch: KVM: Add software breakpoint supportBibo Mao
When VM runs in kvm mode, system will not exit to host mode when executing a general software breakpoint instruction such as INSN_BREAK, trap exception happens in guest mode rather than host mode. In order to debug guest kernel on host side, one mechanism should be used to let VM exit to host mode. Here a hypercall instruction with a special code is used for software breakpoint usage. VM exits to host mode and kvm hypervisor identifies the special hypercall code and sets exit_reason with KVM_EXIT_DEBUG. And then let qemu handle it. Idea comes from ppc kvm, one api KVM_REG_LOONGARCH_DEBUG_INST is added to get the hypercall code. VMM needs get sw breakpoint instruction with this api and set the corresponding sw break point for guest kernel. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-05-06LoongArch: KVM: Add PV IPI support on host sideBibo Mao
On LoongArch system, IPI hw uses iocsr registers. There are one iocsr register access on IPI sending, and two iocsr access on IPI receiving for the IPI interrupt handler. In VM mode all iocsr accessing will cause VM to trap into hypervisor. So with one IPI hw notification there will be three times of trap. In this patch PV IPI is added for VM, hypercall instruction is used for IPI sender, and hypervisor will inject an SWI to the destination vcpu. During the SWI interrupt handler, only CSR.ESTAT register is written to clear irq. CSR.ESTAT register access will not trap into hypervisor, so with PV IPI supported, there is one trap with IPI sender, and no trap with IPI receiver, there is only one trap with IPI notification. Also this patch adds IPI multicast support, the method is similar with x86. With IPI multicast support, IPI notification can be sent to at most 128 vcpus at one time. It greatly reduces the times of trapping into hypervisor. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-05-06LoongArch: KVM: Add cpucfg area for kvm hypervisorBibo Mao
Instruction cpucfg can be used to get processor features. And there is a trap exception when it is executed in VM mode, and also it can be used to provide cpu features to VM. On real hardware cpucfg area 0 - 20 is used by now. Here one specified area 0x40000000 -- 0x400000ff is used for KVM hypervisor to provide PV features, and the area can be extended for other hypervisors in future. This area will never be used for real HW, it is only used by software. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-05-06LoongArch: KVM: Add hypercall instruction emulationBibo Mao
On LoongArch system, there is a hypercall instruction special for virtualization. When system executes this instruction on host side, there is an illegal instruction exception reported, however it will trap into host when it is executed in VM mode. When hypercall is emulated, A0 register is set with value KVM_HCALL_INVALID_CODE, rather than inject EXCCODE_INE invalid instruction exception. So VM can continue to executing the next code. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-12-19LoongArch: KVM: Add LASX (256bit SIMD) supportTianrui Zhao
This patch adds LASX (256bit SIMD) support for LoongArch KVM. There will be LASX exception in KVM when guest use the LASX instructions. KVM will enable LASX and restore the vector registers for guest and then return to guest to continue running. Reviewed-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-12-19LoongArch: KVM: Add LSX (128bit SIMD) supportTianrui Zhao
This patch adds LSX (128bit SIMD) support for LoongArch KVM. There will be LSX exception in KVM when guest use the LSX instructions. KVM will enable LSX and restore the vector registers for guest and then return to guest to continue running. Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-12-19LoongArch: KVM: Remove SW timer switch when vcpu is halt pollingBibo Mao
With halt-polling supported, there is checking for pending events or interrupts when vcpu executes idle instruction. Pending interrupts include injected SW interrupts and passthrough HW interrupts, such as HW timer interrupts, since HW timer works still even if vcpu exists from VM mode. Since HW timer pending interrupt can be set directly with CSR status register, and pending HW timer interrupt checking is used in vcpu block checking function, it is not necessary to switch to SW timer during halt-polling. This patch adds preemption disabling in function kvm_cpu_has_pending_timer(), and removes SW timer switching in idle instruction emulation function. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-10-02LoongArch: KVM: Implement kvm exception vectorsTianrui Zhao
Implement kvm exception vectors, using kvm_fault_tables array to save the handle function pointers and it is used when vcpu handle guest exit. Reviewed-by: Bibo Mao <maobibo@loongson.cn> Tested-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-10-02LoongArch: KVM: Implement handle fpu exceptionTianrui Zhao
Implement handle fpu exception, using kvm_own_fpu() to enable fpu for guest. Reviewed-by: Bibo Mao <maobibo@loongson.cn> Tested-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-10-02LoongArch: KVM: Implement handle mmio exceptionTianrui Zhao
Implement handle mmio exception, setting the mmio info into vcpu_run and return to user space to handle it. Reviewed-by: Bibo Mao <maobibo@loongson.cn> Tested-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-10-02LoongArch: KVM: Implement handle gspr exceptionTianrui Zhao
Implement kvm handle gspr exception interface, including emulate the reading and writing of cpucfg, csr, iocsr resource. Reviewed-by: Bibo Mao <maobibo@loongson.cn> Tested-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-10-02LoongArch: KVM: Implement handle idle exceptionTianrui Zhao
Implement kvm handle LoongArch vcpu idle exception, using kvm_vcpu_block to emulate it. Reviewed-by: Bibo Mao <maobibo@loongson.cn> Tested-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-10-02LoongArch: KVM: Implement handle iocsr exceptionTianrui Zhao
Implement kvm handle vcpu iocsr exception, setting the iocsr info into vcpu_run and return to user space to handle it. Reviewed-by: Bibo Mao <maobibo@loongson.cn> Tested-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-10-02LoongArch: KVM: Implement handle csr exceptionTianrui Zhao
Implement kvm handle LoongArch vcpu exit caused by reading, writing and exchanging csr. Use kvm_vcpu_arch::csr structure to emulate the software registers. Reviewed-by: Bibo Mao <maobibo@loongson.cn> Tested-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>