linux-kernel - Re: [PATCH v19 056/130] KVM: x86/tdp_mmu: Init role member of struct kvm_mmu

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Message-ID: <d394ad9e23cffcf1b06302b3f2d49410c326a4d4.camel@intel.com>
Date: Sat, 20 Apr 2024 19:05:19 +0000
From: "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
To: "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "Yamahata,
 Isaku" <isaku.yamahata@...el.com>
CC: "Zhang, Tina" <tina.zhang@...el.com>, "seanjc@...gle.com"
	<seanjc@...gle.com>, "Yuan, Hang" <hang.yuan@...el.com>, "Huang, Kai"
	<kai.huang@...el.com>, "Chen, Bo2" <chen.bo@...el.com>, "sagis@...gle.com"
	<sagis@...gle.com>, "isaku.yamahata@...il.com" <isaku.yamahata@...il.com>,
	"Aktas, Erdem" <erdemaktas@...gle.com>, "pbonzini@...hat.com"
	<pbonzini@...hat.com>
Subject: Re: [PATCH v19 056/130] KVM: x86/tdp_mmu: Init role member of struct
 kvm_mmu_page at allocation

On Wed, 2024-03-20 at 17:11 -0700, Rick Edgecombe wrote:
> @@ -1378,6 +1375,8 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct
> kvm_page_fault *fault)
>                  * needs to be split.
>                  */
>                 sp = tdp_mmu_alloc_sp(vcpu);
> +               if (!(raw_gfn & kvm_gfn_shared_mask(kvm)))
> +                       kvm_mmu_alloc_private_spt(vcpu, sp);

This will try to allocate the private SP for normal VMs (which have a zero
shared mask), it should be:

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index efed70580922..585c80fb62c5 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -1350,7 +1350,7 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct
kvm_page_fault *fault)
                 * needs to be split.
                 */
                sp = tdp_mmu_alloc_sp(vcpu);
-               if (!(raw_gfn & kvm_gfn_shared_mask(kvm)))
+               if (kvm_is_private_gpa(kvm, raw_gfn << PAGE_SHIFT))
                        kvm_mmu_alloc_private_spt(vcpu, sp);
                tdp_mmu_init_child_sp(sp, &iter);