From: Michael Roth <michael.roth@amd.com>
To: <kvm@vger.kernel.org>
Cc: <linux-coco@lists.linux.dev>, <linux-mm@kvack.org>,
<linux-crypto@vger.kernel.org>, <x86@kernel.org>,
<linux-kernel@vger.kernel.org>, <tglx@linutronix.de>,
<mingo@redhat.com>, <jroedel@suse.de>, <thomas.lendacky@amd.com>,
<hpa@zytor.com>, <ardb@kernel.org>, <pbonzini@redhat.com>,
<seanjc@google.com>, <vkuznets@redhat.com>, <jmattson@google.com>,
<luto@kernel.org>, <dave.hansen@linux.intel.com>,
<slp@redhat.com>, <pgonda@google.com>, <peterz@infradead.org>,
<srinivas.pandruvada@linux.intel.com>, <rientjes@google.com>,
<dovmurik@linux.ibm.com>, <tobin@ibm.com>, <bp@alien8.de>,
<vbabka@suse.cz>, <kirill@shutemov.name>, <ak@linux.intel.com>,
<tony.luck@intel.com>, <marcorr@google.com>,
<sathyanarayanan.kuppuswamy@linux.intel.com>,
<alpergun@google.com>, <dgilbert@redhat.com>, <jarkko@kernel.org>,
<ashish.kalra@amd.com>, <nikunj.dadhania@amd.com>,
<liam.merwick@oracle.com>, <zhi.a.wang@intel.com>,
Brijesh Singh <brijesh.singh@amd.com>
Subject: [PATCH RFC v9 26/51] KVM: SVM: Make AVIC backing, VMSA and VMCB memory allocation SNP safe
Date: Sun, 11 Jun 2023 23:25:34 -0500 [thread overview]
Message-ID: <20230612042559.375660-27-michael.roth@amd.com> (raw)
In-Reply-To: <20230612042559.375660-1-michael.roth@amd.com>
From: Brijesh Singh <brijesh.singh@amd.com>
Implement a workaround for an SNP erratum where the CPU will incorrectly
signal an RMP violation #PF if a hugepage (2mb or 1gb) collides with the
RMP entry of a VMCB, VMSA or AVIC backing page.
When SEV-SNP is globally enabled, the CPU marks the VMCB, VMSA, and AVIC
backing pages as "in-use" via a reserved bit in the corresponding RMP
entry after a successful VMRUN. This is done for _all_ VMs, not just
SNP-Active VMs.
If the hypervisor accesses an in-use page through a writable
translation, the CPU will throw an RMP violation #PF. On early SNP
hardware, if an in-use page is 2mb aligned and software accesses any
part of the associated 2mb region with a hupage, the CPU will
incorrectly treat the entire 2mb region as in-use and signal a spurious
RMP violation #PF.
The recommended is to not use the hugepage for the VMCB, VMSA or
AVIC backing page for similar reasons. Add a generic allocator that will
ensure that the page returns is not hugepage (2mb or 1gb) and is safe to
be used when SEV-SNP is enabled. Also implement similar handling for the
VMCB/VMSA pages of nested guests.
Co-developed-by: Marc Orr <marcorr@google.com>
Signed-off-by: Marc Orr <marcorr@google.com>
Reported-by: Alper Gun <alpergun@google.com> # for nested VMSA case
Co-developed-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
[mdr: squash in nested guest handling from Ashish]
Signed-off-by: Michael Roth <michael.roth@amd.com>
---
arch/x86/include/asm/kvm-x86-ops.h | 1 +
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/lapic.c | 5 ++++-
arch/x86/kvm/svm/nested.c | 2 +-
arch/x86/kvm/svm/sev.c | 33 ++++++++++++++++++++++++++++++
arch/x86/kvm/svm/svm.c | 17 ++++++++++++---
arch/x86/kvm/svm/svm.h | 1 +
7 files changed, 55 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 48f043de2ec0..28456b497198 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -135,6 +135,7 @@ KVM_X86_OP(vcpu_deliver_sipi_vector)
KVM_X86_OP_OPTIONAL_RET0(vcpu_get_apicv_inhibit_reasons);
KVM_X86_OP_OPTIONAL_RET0(gmem_prepare)
KVM_X86_OP_OPTIONAL(gmem_invalidate)
+KVM_X86_OP_OPTIONAL(alloc_apic_backing_page)
#undef KVM_X86_OP
#undef KVM_X86_OP_OPTIONAL
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index c26f76641121..8d2bb3ff66a2 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1743,6 +1743,7 @@ struct kvm_x86_ops {
int (*gmem_prepare)(struct kvm *kvm, struct kvm_memory_slot *slot,
kvm_pfn_t pfn, gfn_t gfn, u8 *max_level);
void (*gmem_invalidate)(struct kvm *kvm, kvm_pfn_t start, kvm_pfn_t end);
+ void *(*alloc_apic_backing_page)(struct kvm_vcpu *vcpu);
};
struct kvm_x86_nested_ops {
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index e542cf285b51..94311938651a 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2769,7 +2769,10 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu, int timer_advance_ns)
vcpu->arch.apic = apic;
- apic->regs = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT);
+ if (kvm_x86_ops.alloc_apic_backing_page)
+ apic->regs = static_call(kvm_x86_alloc_apic_backing_page)(vcpu);
+ else
+ apic->regs = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT);
if (!apic->regs) {
printk(KERN_ERR "malloc apic regs error for vcpu %x\n",
vcpu->vcpu_id);
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 96936ddf1b3c..fb981c8b82c4 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1185,7 +1185,7 @@ int svm_allocate_nested(struct vcpu_svm *svm)
if (svm->nested.initialized)
return 0;
- vmcb02_page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
+ vmcb02_page = snp_safe_alloc_page(&svm->vcpu);
if (!vmcb02_page)
return -ENOMEM;
svm->nested.vmcb02.ptr = page_address(vmcb02_page);
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 2bceb0060880..69b57e8f0a7f 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3104,3 +3104,36 @@ void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector)
break;
}
}
+
+struct page *snp_safe_alloc_page(struct kvm_vcpu *vcpu)
+{
+ unsigned long pfn;
+ struct page *p;
+
+ if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
+ return alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
+
+ /*
+ * Allocate an SNP safe page to workaround the SNP erratum where
+ * the CPU will incorrectly signal an RMP violation #PF if a
+ * hugepage (2mb or 1gb) collides with the RMP entry of VMCB, VMSA
+ * or AVIC backing page. The recommeded workaround is to not use the
+ * hugepage.
+ *
+ * Allocate one extra page, use a page which is not 2mb aligned
+ * and free the other.
+ */
+ p = alloc_pages(GFP_KERNEL_ACCOUNT | __GFP_ZERO, 1);
+ if (!p)
+ return NULL;
+
+ split_page(p, 1);
+
+ pfn = page_to_pfn(p);
+ if (IS_ALIGNED(pfn, PTRS_PER_PMD))
+ __free_page(p++);
+ else
+ __free_page(p + 1);
+
+ return p;
+}
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index eb308c9994f9..065167b42f90 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -668,7 +668,7 @@ static int svm_cpu_init(int cpu)
int ret = -ENOMEM;
memset(sd, 0, sizeof(struct svm_cpu_data));
- sd->save_area = alloc_page(GFP_KERNEL | __GFP_ZERO);
+ sd->save_area = snp_safe_alloc_page(NULL);
if (!sd->save_area)
return ret;
@@ -1381,7 +1381,7 @@ static int svm_vcpu_create(struct kvm_vcpu *vcpu)
svm = to_svm(vcpu);
err = -ENOMEM;
- vmcb01_page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
+ vmcb01_page = snp_safe_alloc_page(vcpu);
if (!vmcb01_page)
goto out;
@@ -1390,7 +1390,7 @@ static int svm_vcpu_create(struct kvm_vcpu *vcpu)
* SEV-ES guests require a separate VMSA page used to contain
* the encrypted register state of the guest.
*/
- vmsa_page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
+ vmsa_page = snp_safe_alloc_page(vcpu);
if (!vmsa_page)
goto error_free_vmcb_page;
@@ -4770,6 +4770,16 @@ static int svm_vm_init(struct kvm *kvm)
return 0;
}
+static void *svm_alloc_apic_backing_page(struct kvm_vcpu *vcpu)
+{
+ struct page *page = snp_safe_alloc_page(vcpu);
+
+ if (!page)
+ return NULL;
+
+ return page_address(page);
+}
+
static struct kvm_x86_ops svm_x86_ops __initdata = {
.name = KBUILD_MODNAME,
@@ -4900,6 +4910,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
.vcpu_deliver_sipi_vector = svm_vcpu_deliver_sipi_vector,
.vcpu_get_apicv_inhibit_reasons = avic_vcpu_get_apicv_inhibit_reasons,
+ .alloc_apic_backing_page = svm_alloc_apic_backing_page,
};
/*
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 1ab117daebd9..e45b54e95495 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -741,6 +741,7 @@ void sev_es_vcpu_reset(struct vcpu_svm *svm);
void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector);
void sev_es_prepare_switch_to_guest(struct sev_es_save_area *hostsa);
void sev_es_unmap_ghcb(struct vcpu_svm *svm);
+struct page *snp_safe_alloc_page(struct kvm_vcpu *vcpu);
/* vmenter.S */
--
2.25.1
next prev parent reply other threads:[~2023-06-12 4:38 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-12 4:25 [PATCH RFC v9 00/51] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 01/51] KVM: x86: Add gmem hook for initializing private memory Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 02/51] KVM: x86: Add gmem hook for invalidating " Michael Roth
2023-06-12 10:49 ` Borislav Petkov
2023-06-19 13:39 ` Borislav Petkov
2023-06-12 4:25 ` [PATCH RFC v9 03/51] KVM: x86: Use full 64-bit error code for kvm_mmu_do_page_fault Michael Roth
2023-06-14 14:24 ` Isaku Yamahata
2023-06-12 4:25 ` [PATCH RFC v9 04/51] KVM: x86: Determine shared/private faults using a configurable mask Michael Roth
2023-06-14 16:47 ` Isaku Yamahata
2023-06-20 20:28 ` Michael Roth
2023-06-20 21:18 ` Isaku Yamahata
2023-06-21 23:00 ` Michael Roth
2023-06-22 8:01 ` Isaku Yamahata
2023-06-22 9:55 ` Huang, Kai
2023-06-22 15:32 ` Michael Roth
2023-06-22 22:31 ` Huang, Kai
2023-06-22 23:39 ` Isaku Yamahata
2023-06-22 23:52 ` Huang, Kai
2023-06-23 14:43 ` Isaku Yamahata
2023-06-19 16:27 ` Borislav Petkov
2023-06-20 20:36 ` Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 05/51] x86/coco: move CONFIG_HAS_CC_PLATFORM check down into coco/Makefile Michael Roth
2023-06-12 7:07 ` Kirill A . Shutemov
2023-06-20 12:09 ` Borislav Petkov
2023-06-20 20:43 ` Michael Roth
2023-06-21 8:54 ` Borislav Petkov
2023-06-29 21:02 ` Michael Roth
2023-07-10 3:05 ` Sathyanarayanan Kuppuswamy
2023-07-10 13:11 ` Tom Lendacky
2023-06-12 4:25 ` [PATCH RFC v9 06/51] x86/cpufeatures: Add SEV-SNP CPU feature Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 07/51] x86/sev: Add the host SEV-SNP initialization support Michael Roth
2023-06-12 15:34 ` Dave Hansen
2023-06-21 9:15 ` Borislav Petkov
2023-06-21 14:31 ` Dave Hansen
2023-06-21 15:59 ` Borislav Petkov
2023-06-21 9:42 ` Borislav Petkov
2023-06-21 14:36 ` Tom Lendacky
2023-06-21 19:15 ` Kalra, Ashish
2023-08-09 13:03 ` Jeremi Piotrowski
2023-06-12 4:25 ` [PATCH RFC v9 08/51] x86/speculation: Do not enable Automatic IBRS if SEV SNP is enabled Michael Roth
2023-06-12 15:39 ` Dave Hansen
2023-07-18 22:34 ` Kim Phillips
2023-07-18 23:17 ` Dave Hansen
2023-07-20 19:11 ` Kim Phillips
2023-07-20 22:24 ` Dave Hansen
2023-07-21 16:56 ` Kim Phillips
2023-06-12 4:25 ` [PATCH RFC v9 09/51] x86/sev: Add RMP entry lookup helpers Michael Roth
2023-06-12 16:08 ` Dave Hansen
2023-06-30 21:57 ` Michael Roth
2023-06-30 22:29 ` Dave Hansen
2023-06-12 4:25 ` [PATCH RFC v9 10/51] x86/fault: Add helper for dumping RMP entries Michael Roth
2023-06-12 16:12 ` Dave Hansen
2023-06-12 4:25 ` [PATCH RFC v9 11/51] x86/traps: Define RMP violation #PF error code Michael Roth
2023-06-12 16:26 ` Dave Hansen
2023-06-12 4:25 ` [PATCH RFC v9 12/51] x86/fault: Report RMP page faults for kernel addresses Michael Roth
2023-06-12 16:30 ` Dave Hansen
2023-06-12 4:25 ` [PATCH RFC v9 13/51] x86/fault: Handle RMP page faults for user addresses Michael Roth
2023-06-12 16:40 ` Dave Hansen
2023-06-12 4:25 ` [PATCH RFC v9 14/51] x86/sev: Add helper functions for RMPUPDATE and PSMASH instruction Michael Roth
2023-06-12 17:00 ` Dave Hansen
2023-06-12 4:25 ` [PATCH RFC v9 15/51] x86/sev: Invalidate pages from the direct map when adding them to the RMP table Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 16/51] crypto: ccp: Define the SEV-SNP commands Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 17/51] crypto: ccp: Add support to initialize the AMD-SP for SEV-SNP Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 18/51] crypto: ccp: Provide API to issue SEV and SNP commands Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 19/51] x86/sev: Introduce snp leaked pages list Michael Roth
2023-08-09 12:46 ` Jeremi Piotrowski
2023-06-12 4:25 ` [PATCH RFC v9 20/51] crypto: ccp: Handle the legacy TMR allocation when SNP is enabled Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 21/51] crypto: ccp: Handle the legacy SEV command " Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 22/51] crypto: ccp: Add the SNP_PLATFORM_STATUS command Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 23/51] KVM: SEV: Select CONFIG_KVM_PROTECTED_VM when CONFIG_KVM_AMD_SEV=y Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 24/51] KVM: SVM: Add support to handle AP reset MSR protocol Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 25/51] KVM: SVM: Add GHCB handling for Hypervisor Feature Support requests Michael Roth
2023-06-12 4:25 ` Michael Roth [this message]
2023-06-12 4:25 ` [PATCH RFC v9 27/51] KVM: SVM: Add initial SEV-SNP support Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 28/51] KVM: SVM: Add KVM_SNP_INIT command Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 29/51] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_START command Michael Roth
2023-06-12 17:08 ` Peter Gonda
2023-06-12 4:25 ` [PATCH RFC v9 30/51] KVM: Add HVA range operator Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 31/51] KVM: Split out memory attribute xarray updates to helper function Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 32/51] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_UPDATE command Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 33/51] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_FINISH command Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 34/51] KVM: SVM: Add support to handle GHCB GPA register VMGEXIT Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 35/51] KVM: SVM: Add KVM_EXIT_VMGEXIT Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 36/51] KVM: SVM: Add support to handle MSR based Page State Change VMGEXIT Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 37/51] KVM: SVM: Add support to handle " Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 38/51] KVM: x86: Export the kvm_zap_gfn_range() for the SNP use Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 39/51] KVM: x86: Define RMP page fault error bits for #NPF Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 40/51] KVM: SVM: Add support to handle RMP nested page faults Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 41/51] KVM: SVM: Use a VMSA physical address variable for populating VMCB Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 42/51] KVM: SVM: Support SEV-SNP AP Creation NAE event Michael Roth
2023-08-15 16:00 ` Peter Gonda
2023-06-12 4:25 ` [PATCH RFC v9 43/51] KVM: SEV: Configure MMU to check for private fault flags Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 44/51] KVM: SEV: Implement gmem hook for initializing private pages Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 45/51] KVM: SEV: Implement gmem hook for invalidating " Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 46/51] KVM: SVM: Add module parameter to enable the SEV-SNP Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 47/51] iommu/amd: Add IOMMU_SNP_SHUTDOWN support Michael Roth
2023-09-07 10:31 ` Suthikulpanit, Suravee
2023-06-12 4:25 ` [PATCH RFC v9 48/51] crypto: ccp: Add the SNP_{SET,GET}_EXT_CONFIG command Michael Roth
2023-06-13 6:24 ` Alexey Kardashevskiy
2023-06-12 4:25 ` [PATCH RFC v9 49/51] x86/sev: Add KVM commands for per-instance certs Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 50/51] KVM: SVM: Provide support for SNP_GUEST_REQUEST NAE event Michael Roth
2023-06-12 4:25 ` [PATCH RFC v9 51/51] crypto: ccp: Add debug support for decrypting pages Michael Roth
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