From: Tom Lendacky <thomas.lendacky@amd.com>
To: Wei Huang <wei.huang2@amd.com>, kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, pbonzini@redhat.com,
vkuznets@redhat.com, seanjc@google.com, wanpengli@tencent.com,
jmattson@google.com, joro@8bytes.org, tglx@linutronix.de,
mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com
Subject: Re: [PATCH v3 2/3] KVM: x86: Handle the case of 5-level shadow page table
Date: Wed, 18 Aug 2021 13:00:14 -0500 [thread overview]
Message-ID: <49f37adb-973c-aec6-9b9e-30699113af18@amd.com> (raw)
In-Reply-To: <20210818165549.3771014-3-wei.huang2@amd.com>
On 8/18/21 11:55 AM, Wei Huang wrote:
> When the 5-level page table CPU flag is exposed, KVM code needs to handle
> this case by pointing mmu->root_hpa to a properly-constructed 5-level page
> table.
>
> Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Wei Huang <wei.huang2@amd.com>
> ---
...
> pml4_root = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT);
> - if (!pml4_root) {
> - free_page((unsigned long)pae_root);
> - return -ENOMEM;
> + if (!pml4_root)
> + goto err_pml4;
> +
> + if (mmu->shadow_root_level > PT64_ROOT_4LEVEL) {
> + pml5_root = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT);
> + if (!pml5_root)
> + goto err_pml5;
> }
>
> mmu->pae_root = pae_root;
> mmu->pml4_root = pml4_root;
> + mmu->pml5_root = pml5_root;
It looks like pml5_root could be used uninitialized here. You should
initialize it to NULL or set it to NULL as an else path of the new check
above.
Thanks,
Tom
>
> return 0;
> +err_pml5:
> + free_page((unsigned long)pml4_root);
> +err_pml4:
> + free_page((unsigned long)pae_root);
> + return -ENOMEM;
> }
>
> void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
> @@ -5364,6 +5377,7 @@ static void free_mmu_pages(struct kvm_mmu *mmu)
> set_memory_encrypted((unsigned long)mmu->pae_root, 1);
> free_page((unsigned long)mmu->pae_root);
> free_page((unsigned long)mmu->pml4_root);
> + free_page((unsigned long)mmu->pml5_root);
> }
>
> static int __kvm_mmu_create(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu)
>
next prev parent reply other threads:[~2021-08-18 18:00 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-18 16:55 [PATCH v3 0/3] SVM 5-level page table support Wei Huang
2021-08-18 16:55 ` [PATCH v3 1/3] KVM: x86: Allow CPU to force vendor-specific TDP level Wei Huang
2021-08-18 16:55 ` [PATCH v3 2/3] KVM: x86: Handle the case of 5-level shadow page table Wei Huang
2021-08-18 17:15 ` Sean Christopherson
2021-08-19 16:36 ` Paolo Bonzini
2021-08-18 18:00 ` Tom Lendacky [this message]
2021-08-18 16:55 ` [PATCH v3 3/3] KVM: SVM: Add 5-level page table support for SVM Wei Huang
2021-08-18 17:32 ` Sean Christopherson
2021-08-19 16:38 ` Paolo Bonzini
2021-08-19 16:43 ` [PATCH v3 0/3] SVM 5-level page table support Paolo Bonzini
2021-08-23 9:20 ` Maxim Levitsky
2021-08-23 15:15 ` Wei Huang
2021-08-23 16:10 ` Sean Christopherson
2021-08-23 18:10 ` Maxim Levitsky
2021-08-23 18:06 ` Maxim Levitsky
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