On 2024/8/28 上午10:08, Huacai Chen wrote:
Hi, Bibo,
I have consulted with Jiaxun offline, and he has tried his best to
propose a "scratch vcpu" solution. But unfortunately that solution is
too difficult to implement and he has nearly given up.
So the solution in this series seems the best one, and I will queue it
for loongarch-kvm now.
Thanks. There may be requirement such as there is different capability
for different vCPUs, only that it is a little far from now. We can
discuss and add that if there is such requirement. Because of limitation
of human resource and ability, the implementation is not perfect however
it can be used.
Regards
Bibo Mao
Huacai
On Tue, Jul 30, 2024 at 3:57 PM Bibo Mao <maobibo@xxxxxxxxxxx> wrote:
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 lately enabling method is used for LBT. LBT
context is saved/restored during vcpu context switch path.
Also this patch set LBT capability detection, and LBT register get and set
interface for userspace vmm, so that vm supports migration with BT
extension.
---
v5 ... v6:
1. Solve compiling issue with function kvm_get_one_reg() and
kvm_set_one_reg().
v4 ... v5:
1. Add feature detection for LSX/LASX from vm side, previously
LSX/LASX feature is detected from vcpu ioctl command, now both
methods are supported.
v3 ... v4:
1. Merge LBT feature detection for VM and VCPU into one patch.
2. Move function declaration such as kvm_lose_lbt()/kvm_check_fcsr()/
kvm_enable_lbt_fpu() from header file to c file, since it is only
used in one c file.
v2 ... v3:
1. Split KVM_LOONGARCH_VM_FEAT_LBT capability checking into three
sub-features, KVM_LOONGARCH_VM_FEAT_X86BT/KVM_LOONGARCH_VM_FEAT_ARMBT
and KVM_LOONGARCH_VM_FEAT_MIPSBT. Return success only if host
supports the sub-feature.
v1 ... v2:
1. With LBT register read or write interface to userpace, replace
device attr method with KVM_GET_ONE_REG method, since lbt register is
vcpu register and can be added in kvm_reg_list in future.
2. Add vm device attr ctrl marcro KVM_LOONGARCH_VM_FEAT_CTRL, it is
used to get supported LBT feature before vm or vcpu is created.
---
Bibo Mao (3):
LoongArch: KVM: Add HW Binary Translation extension support
LoongArch: KVM: Add LBT feature detection function
LoongArch: KVM: Add vm migration support for LBT registers
arch/loongarch/include/asm/kvm_host.h | 8 ++
arch/loongarch/include/asm/kvm_vcpu.h | 6 ++
arch/loongarch/include/uapi/asm/kvm.h | 17 ++++
arch/loongarch/kvm/exit.c | 9 ++
arch/loongarch/kvm/vcpu.c | 128 +++++++++++++++++++++++++-
arch/loongarch/kvm/vm.c | 52 ++++++++++-
6 files changed, 218 insertions(+), 2 deletions(-)
base-commit: 8400291e289ee6b2bf9779ff1c83a291501f017b
--
2.39.3
