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path: root/arch/loongarch/include/asm/kvm_para.h
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2024-09-12LoongArch: KVM: Implement function kvm_para_has_feature()Bibo Mao1-0/+10
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>
2024-09-12LoongArch: KVM: Enable paravirt feature control from VMMBibo Mao1-0/+2
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>
2024-08-07LoongArch: KVM: Remove undefined a6 argument comment for kvm_hypercall()Dandan Zhang1-2/+2
The kvm_hypercall() set for LoongArch is limited to a1-a5. So the mention of a6 in the comment is undefined that needs to be rectified. Reviewed-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Wentao Guan <guanwentao@uniontech.com> Signed-off-by: Dandan Zhang <zhangdandan@uniontech.com> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-07-09LoongArch: KVM: Add PV steal time support in host sideBibo Mao1-0/+11
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>
2024-05-06LoongArch: KVM: Add software breakpoint supportBibo Mao1-0/+3
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 Mao1-0/+131
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 hypercall instruction emulationBibo Mao1-0/+27
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>