From 062ac0cb83837fab2afdb817f136d0f8860474e9 Mon Sep 17 00:00:00 2001 From: Bibo Mao Date: Tue, 18 Mar 2025 16:48:08 +0800 Subject: [PATCH] LoongArch: KVM: Remove PGD saving during VM context switch PGD table for primary mmu keeps unchanged once VM is created, it is not necessary to save PGD table pointer during VM context switch. And it can be acquired when VM is created. Signed-off-by: Bibo Mao Signed-off-by: Huacai Chen --- arch/loongarch/include/asm/kvm_host.h | 3 +++ arch/loongarch/kernel/asm-offsets.c | 1 + arch/loongarch/kvm/switch.S | 12 ++---------- arch/loongarch/kvm/vcpu.c | 9 +++++++++ 4 files changed, 15 insertions(+), 10 deletions(-) diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h index 590982cd986e..d8b543b3fa25 100644 --- a/arch/loongarch/include/asm/kvm_host.h +++ b/arch/loongarch/include/asm/kvm_host.h @@ -176,6 +176,9 @@ struct kvm_vcpu_arch { /* Pointers stored here for easy accessing from assembly code */ int (*handle_exit)(struct kvm_run *run, struct kvm_vcpu *vcpu); + /* GPA (=HVA) of PGD for secondary mmu */ + unsigned long kvm_pgd; + /* Host registers preserved across guest mode execution */ unsigned long host_sp; unsigned long host_tp; diff --git a/arch/loongarch/kernel/asm-offsets.c b/arch/loongarch/kernel/asm-offsets.c index 8be1c38ad8eb..c19f446ad0db 100644 --- a/arch/loongarch/kernel/asm-offsets.c +++ b/arch/loongarch/kernel/asm-offsets.c @@ -296,6 +296,7 @@ static void __used output_kvm_defines(void) OFFSET(KVM_ARCH_HSP, kvm_vcpu_arch, host_sp); OFFSET(KVM_ARCH_HTP, kvm_vcpu_arch, host_tp); OFFSET(KVM_ARCH_HPGD, kvm_vcpu_arch, host_pgd); + OFFSET(KVM_ARCH_KVMPGD, kvm_vcpu_arch, kvm_pgd); OFFSET(KVM_ARCH_HANDLE_EXIT, kvm_vcpu_arch, handle_exit); OFFSET(KVM_ARCH_HEENTRY, kvm_vcpu_arch, host_eentry); OFFSET(KVM_ARCH_GEENTRY, kvm_vcpu_arch, guest_eentry); diff --git a/arch/loongarch/kvm/switch.S b/arch/loongarch/kvm/switch.S index 1be185e94807..f1768b7a6194 100644 --- a/arch/loongarch/kvm/switch.S +++ b/arch/loongarch/kvm/switch.S @@ -60,16 +60,8 @@ ld.d t0, a2, KVM_ARCH_GPC csrwr t0, LOONGARCH_CSR_ERA - /* Save host PGDL */ - csrrd t0, LOONGARCH_CSR_PGDL - st.d t0, a2, KVM_ARCH_HPGD - - /* Switch to kvm */ - ld.d t1, a2, KVM_VCPU_KVM - KVM_VCPU_ARCH - - /* Load guest PGDL */ - li.w t0, KVM_GPGD - ldx.d t0, t1, t0 + /* Load PGD for KVM hypervisor */ + ld.d t0, a2, KVM_ARCH_KVMPGD csrwr t0, LOONGARCH_CSR_PGDL /* Mix GID and RID */ diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c index 9e1a9b4aa4c6..a147290a11e4 100644 --- a/arch/loongarch/kvm/vcpu.c +++ b/arch/loongarch/kvm/vcpu.c @@ -1462,6 +1462,15 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) hrtimer_init(&vcpu->arch.swtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD); vcpu->arch.swtimer.function = kvm_swtimer_wakeup; + /* Get GPA (=HVA) of PGD for kvm hypervisor */ + vcpu->arch.kvm_pgd = __pa(vcpu->kvm->arch.pgd); + + /* + * Get PGD for primary mmu, virtual address is used since there is + * memory access after loading from CSR_PGD in tlb exception fast path. + */ + vcpu->arch.host_pgd = (unsigned long)vcpu->kvm->mm->pgd; + vcpu->arch.handle_exit = kvm_handle_exit; vcpu->arch.guest_eentry = (unsigned long)kvm_loongarch_ops->exc_entry; vcpu->arch.csr = kzalloc(sizeof(struct loongarch_csrs), GFP_KERNEL); -- 2.50.1