Re: [PATCH v2 5/7] KVM: SVM: hyper-v: Remote TLB flush for SVM

Vitaly Kuznetsov
2021-04-16T09:05:10Z

Vineeth Pillai <viremana@linux.microsoft.com> writes:

> Enable remote TLB flush for SVM.
>
> Signed-off-by: Vineeth Pillai <viremana@linux.microsoft.com>
> ---
> arch/x86/kvm/svm/svm.c | 37 +++++++++++++++++++++++++++++++++++++
> 1 file changed, 37 insertions(+)
>
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 2ad1f55c88d0..de141d5ae5fb 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -37,6 +37,7 @@
> #include <asm/spec-ctrl.h>
> #include <asm/cpu_device_id.h>
> #include <asm/traps.h>
> +#include <asm/mshyperv.h>
>
> #include <asm/virtext.h>
> #include "trace.h"
> @@ -44,6 +45,8 @@
> #include "svm.h"
> #include "svm_ops.h"
>
> +#include "hyperv.h"
> +
> #define __ex(x) __kvm_handle_fault_on_reboot(x)
>
> MODULE_AUTHOR("Qumranet");
> @@ -931,6 +934,8 @@ static __init void svm_set_cpu_caps(void)
> kvm_cpu_cap_set(X86_FEATURE_VIRT_SSBD);
> }
>
> +static struct kvm_x86_ops svm_x86_ops;
> +
> static __init int svm_hardware_setup(void)
> {
> int cpu;
> @@ -1000,6 +1005,16 @@ static __init int svm_hardware_setup(void)
> kvm_configure_mmu(npt_enabled, get_max_npt_level(), PG_LEVEL_1G);
> pr_info("kvm: Nested Paging %sabled\n", npt_enabled ? "en" : "dis");
>
> +#if IS_ENABLED(CONFIG_HYPERV)
> + if (ms_hyperv.nested_features & HV_X64_NESTED_ENLIGHTENED_TLB
> + && npt_enabled) {
> + pr_info("kvm: Hyper-V enlightened NPT TLB flush enabled\n");
> + svm_x86_ops.tlb_remote_flush = kvm_hv_remote_flush_tlb;
> + svm_x86_ops.tlb_remote_flush_with_range =
> + kvm_hv_remote_flush_tlb_with_range;
> + }
> +#endif
> +
> if (nrips) {
> if (!boot_cpu_has(X86_FEATURE_NRIPS))
> nrips = false;
> @@ -1120,6 +1135,21 @@ static void svm_check_invpcid(struct vcpu_svm *svm)
> }
> }
>
> +#if IS_ENABLED(CONFIG_HYPERV)
> +static void hv_init_vmcb(struct vmcb *vmcb)
> +{
> + struct hv_enlightenments *hve = &vmcb->hv_enlightenments;
> +
> + if (npt_enabled &&
> + ms_hyperv.nested_features & HV_X64_NESTED_ENLIGHTENED_TLB)

Nitpick: we can probably have a 'static inline' for

"npt_enabled && ms_hyperv.nested_features & HV_X64_NESTED_ENLIGHTENED_TLB"

e.g. 'hv_svm_enlightened_tlbflush()'

> + hve->hv_enlightenments_control.enlightened_npt_tlb = 1;
> +}
> +#else
> +static inline void hv_init_vmcb(struct vmcb *vmcb)
> +{
> +}
> +#endif
> +
> static void init_vmcb(struct vcpu_svm *svm)
> {
> struct vmcb_control_area *control = &svm->vmcb->control;
> @@ -1282,6 +1312,8 @@ static void init_vmcb(struct vcpu_svm *svm)
> }
> }
>
> + hv_init_vmcb(svm->vmcb);
> +
> vmcb_mark_all_dirty(svm->vmcb);
>
> enable_gif(svm);
> @@ -3975,6 +4007,11 @@ static void svm_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long root,
> svm->vmcb->control.nested_cr3 = cr3;
> vmcb_mark_dirty(svm->vmcb, VMCB_NPT);
>
> +#if IS_ENABLED(CONFIG_HYPERV)
> + if (kvm_x86_ops.tlb_remote_flush)
> + kvm_update_arch_tdp_pointer(vcpu->kvm, vcpu, cr3);
> +#endif
> +
> /* Loading L2's CR3 is handled by enter_svm_guest_mode. */
> if (!test_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail))
> return;

--
Vitaly