[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20221122100705.GA619277@chaop.bj.intel.com>
Date: Tue, 22 Nov 2022 18:07:05 +0800
From: Chao Peng <chao.p.peng@...ux.intel.com>
To: Vishal Annapurve <vannapurve@...gle.com>
Cc: x86@...nel.org, kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-kselftest@...r.kernel.org, pbonzini@...hat.com,
vkuznets@...hat.com, wanpengli@...cent.com, jmattson@...gle.com,
joro@...tes.org, tglx@...utronix.de, mingo@...hat.com,
bp@...en8.de, dave.hansen@...ux.intel.com, hpa@...or.com,
shuah@...nel.org, yang.zhong@...el.com, ricarkol@...gle.com,
aaronlewis@...gle.com, wei.w.wang@...el.com,
kirill.shutemov@...ux.intel.com, corbet@....net, hughd@...gle.com,
jlayton@...nel.org, bfields@...ldses.org,
akpm@...ux-foundation.org, yu.c.zhang@...ux.intel.com,
jun.nakajima@...el.com, dave.hansen@...el.com,
michael.roth@....com, qperret@...gle.com, steven.price@....com,
ak@...ux.intel.com, david@...hat.com, luto@...nel.org,
vbabka@...e.cz, marcorr@...gle.com, erdemaktas@...gle.com,
pgonda@...gle.com, nikunj@....com, seanjc@...gle.com,
diviness@...gle.com, maz@...nel.org, dmatlack@...gle.com,
axelrasmussen@...gle.com, maciej.szmigiero@...cle.com,
mizhang@...gle.com, bgardon@...gle.com, ackerleytng@...gle.com
Subject: Re: [V1 PATCH 1/6] KVM: x86: Add support for testing private memory
On Fri, Nov 11, 2022 at 01:42:39AM +0000, Vishal Annapurve wrote:
> Introduce HAVE_KVM_PRIVATE_MEM_TESTING config to be able to test fd based
> approach to support private memory with non-confidential selftest VMs.
> To support this testing few important aspects need to be considered from
> the perspective of selftests -
> * KVM needs to know whether the access from guest VM is private or shared.
> Confidential VMs (SNP/TDX) carry a dedicated bit in gpa that can be used by
> KVM to deduce the nature of the access.
> Non-confidential VMs don't have mechanism to carry/convey such an
> information to KVM. So KVM just relies on what attributes are set by
> userspace VMM keeping the userspace VMM in the TCB for the testing
> purposes.
> * arch_private_mem_supported is updated to allow private memory logic to
> work with non-confidential vm selftests.
>
> Signed-off-by: Vishal Annapurve <vannapurve@...gle.com>
> ---
> arch/x86/kvm/mmu/mmu.c | 4 ++++
> arch/x86/kvm/mmu/mmu_internal.h | 4 +++-
> virt/kvm/Kconfig | 4 ++++
> virt/kvm/kvm_main.c | 2 +-
> 4 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 10017a9f26ee..b3118d00b284 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -4280,6 +4280,10 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
>
> fault->gfn = fault->addr >> PAGE_SHIFT;
> fault->slot = kvm_vcpu_gfn_to_memslot(vcpu, fault->gfn);
> +#ifdef CONFIG_HAVE_KVM_PRIVATE_MEM_TESTING
> + fault->is_private = kvm_slot_can_be_private(fault->slot) &&
> + kvm_mem_is_private(vcpu->kvm, fault->gfn);
> +#endif
>
> if (page_fault_handle_page_track(vcpu, fault))
> return RET_PF_EMULATE;
> diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
> index 5cdff5ca546c..2e759f39c2c5 100644
> --- a/arch/x86/kvm/mmu/mmu_internal.h
> +++ b/arch/x86/kvm/mmu/mmu_internal.h
> @@ -188,7 +188,6 @@ struct kvm_page_fault {
>
> /* Derived from mmu and global state. */
> const bool is_tdp;
> - const bool is_private;
> const bool nx_huge_page_workaround_enabled;
>
> /*
> @@ -221,6 +220,9 @@ struct kvm_page_fault {
> /* The memslot containing gfn. May be NULL. */
> struct kvm_memory_slot *slot;
>
> + /* Derived from encryption bits of the faulting GPA for CVMs. */
> + bool is_private;
Either we can wrap it with the CONFIG_HAVE_KVM_PRIVATE_MEM_TESTING or if
it looks ugly I can remove the "const" in my code.
Chao
> +
> /* Outputs of kvm_faultin_pfn. */
> kvm_pfn_t pfn;
> hva_t hva;
> diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
> index 69ca59e82149..300876afb0ca 100644
> --- a/virt/kvm/Kconfig
> +++ b/virt/kvm/Kconfig
> @@ -93,3 +93,7 @@ config HAVE_KVM_RESTRICTED_MEM
> config KVM_GENERIC_PRIVATE_MEM
> bool
> depends on HAVE_KVM_RESTRICTED_MEM
> +
> +config HAVE_KVM_PRIVATE_MEM_TESTING
> + bool
> + depends on KVM_GENERIC_PRIVATE_MEM
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index dae6a2c196ad..54e57b7f1c15 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -1750,7 +1750,7 @@ static void kvm_replace_memslot(struct kvm *kvm,
>
> bool __weak kvm_arch_has_private_mem(struct kvm *kvm)
> {
> - return false;
> + return IS_ENABLED(CONFIG_HAVE_KVM_PRIVATE_MEM_TESTING);
> }
>
> static int check_memory_region_flags(struct kvm *kvm,
> --
> 2.38.1.431.g37b22c650d-goog
Powered by blists - more mailing lists