From: Sean Christopherson <seanjc@google.com>
To: Binbin Wu <binbin.wu@linux.intel.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
pbonzini@redhat.com, chao.gao@intel.com, kai.huang@intel.com,
David.Laight@aculab.com, robert.hu@linux.intel.com,
guang.zeng@intel.com
Subject: Re: [PATCH v11 08/16] KVM: x86: Introduce get_untagged_addr() in kvm_x86_ops and call it in emulator
Date: Mon, 23 Oct 2023 16:30:40 -0700 [thread overview]
Message-ID: <ZTcCIPHMeX84auh-@google.com> (raw)
In-Reply-To: <20230913124227.12574-9-binbin.wu@linux.intel.com>
On Wed, Sep 13, 2023, Binbin Wu wrote:
> Introduce a new interface get_untagged_addr() to kvm_x86_ops to untag
> the metadata from linear address. Call the interface in linearization
> of instruction emulator for 64-bit mode.
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index ea48ba87dacf..e03313287816 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -8308,6 +8308,15 @@ static void emulator_vm_bugged(struct x86_emulate_ctxt *ctxt)
> kvm_vm_bugged(kvm);
> }
>
> +static gva_t emulator_get_untagged_addr(struct x86_emulate_ctxt *ctxt,
> + gva_t addr, unsigned int flags)
> +{
> + if (!kvm_x86_ops.get_untagged_addr)
> + return addr;
> +
> + return static_call(kvm_x86_get_untagged_addr)(emul_to_vcpu(ctxt), addr, flags);
> +}
> +
> static const struct x86_emulate_ops emulate_ops = {
> .vm_bugged = emulator_vm_bugged,
> .read_gpr = emulator_read_gpr,
> @@ -8352,6 +8361,7 @@ static const struct x86_emulate_ops emulate_ops = {
> .leave_smm = emulator_leave_smm,
> .triple_fault = emulator_triple_fault,
> .set_xcr = emulator_set_xcr,
> + .get_untagged_addr = emulator_get_untagged_addr,
Oh, and for posterity because I've now thought about this on two separate occasions:
We _could_ nullify .get_untagged_addr() if LAM isn't supported, e.g. to save a
RETPOLINE when applicable, but that would require making emulate_ops non-const,
and so I think it's worth eating the indirect call. I suppose we could gate it
on CONFIG_ADDRESS_MASKING, but then we'd have to carry a bunch of #ifdefs in the
VMX code, so I don't think that's worth doing either.
next prev parent reply other threads:[~2023-10-23 23:30 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-13 12:42 [PATCH v11 00/16] LAM and LASS KVM Enabling Binbin Wu
2023-09-13 12:42 ` [PATCH v11 01/16] KVM: x86: Consolidate flags for __linearize() Binbin Wu
2023-09-13 12:42 ` [PATCH v11 02/16] KVM: x86: Use a new flag for branch targets Binbin Wu
2023-10-23 16:20 ` Sean Christopherson
2023-09-13 12:42 ` [PATCH v11 03/16] KVM: x86: Add an emulation flag for implicit system access Binbin Wu
2023-09-13 12:42 ` [PATCH v11 04/16] KVM: x86: Add X86EMUL_F_INVLPG and pass it in em_invlpg() Binbin Wu
2023-09-13 12:42 ` [PATCH v11 05/16] KVM: x86/mmu: Drop non-PA bits when getting GFN for guest's PGD Binbin Wu
2023-09-13 12:42 ` [PATCH v11 06/16] KVM: x86: Add & use kvm_vcpu_is_legal_cr3() to check CR3's legality Binbin Wu
2023-09-13 12:42 ` [PATCH v11 07/16] KVM: x86: Remove kvm_vcpu_is_illegal_gpa() Binbin Wu
2023-09-13 12:42 ` [PATCH v11 08/16] KVM: x86: Introduce get_untagged_addr() in kvm_x86_ops and call it in emulator Binbin Wu
2023-10-23 23:14 ` Sean Christopherson
2023-10-23 23:30 ` Sean Christopherson [this message]
2023-09-13 12:42 ` [PATCH v11 09/16] KVM: x86: Untag address for vmexit handlers when LAM applicable Binbin Wu
2023-09-13 12:42 ` [PATCH v11 10/16] KVM: x86: Virtualize LAM for supervisor pointer Binbin Wu
2023-09-13 12:42 ` [PATCH v11 11/16] KVM: x86: Virtualize LAM for user pointer Binbin Wu
2023-09-13 12:42 ` [PATCH v11 12/16] KVM: x86: Advertise and enable LAM (user and supervisor) Binbin Wu
2023-09-13 12:42 ` [PATCH v11 13/16] KVM: x86: Use KVM-governed feature framework to track "LAM enabled" Binbin Wu
2023-09-13 12:42 ` [PATCH v11 14/16] KVM: emulator: Add emulation of LASS violation checks on linear address Binbin Wu
2023-09-13 12:42 ` [PATCH v11 15/16] KVM: VMX: Virtualize LASS Binbin Wu
2023-09-13 12:42 ` [PATCH v11 16/16] KVM: x86: Advertise LASS CPUID to user space Binbin Wu
2023-10-08 9:37 ` [PATCH v11 00/16] LAM and LASS KVM Enabling Binbin Wu
2023-10-10 23:48 ` Sean Christopherson
2023-10-21 0:26 ` Sean Christopherson
2023-10-21 0:34 ` Sean Christopherson
2023-10-22 12:35 ` Binbin Wu
2023-10-23 23:43 ` Sean Christopherson
2023-10-24 8:31 ` Binbin Wu
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