From: Michael Roth <michael.roth@amd.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: <kvm@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
Sean Christopherson <seanjc@google.com>
Subject: [PULL 12/19] KVM: SEV: Implement gmem hook for initializing private pages
Date: Fri, 10 May 2024 16:10:17 -0500 [thread overview]
Message-ID: <20240510211024.556136-13-michael.roth@amd.com> (raw)
In-Reply-To: <20240510211024.556136-1-michael.roth@amd.com>
This will handle the RMP table updates needed to put a page into a
private state before mapping it into an SEV-SNP guest.
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Message-ID: <20240501085210.2213060-14-michael.roth@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/Kconfig | 1 +
arch/x86/kvm/svm/sev.c | 98 ++++++++++++++++++++++++++++++++++++++++++
arch/x86/kvm/svm/svm.c | 2 +
arch/x86/kvm/svm/svm.h | 5 +++
arch/x86/kvm/x86.c | 5 +++
virt/kvm/guest_memfd.c | 4 +-
6 files changed, 113 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index 5e72faca4e8f..10768f13b240 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -137,6 +137,7 @@ config KVM_AMD_SEV
depends on CRYPTO_DEV_SP_PSP && !(KVM_AMD=y && CRYPTO_DEV_CCP_DD=m)
select ARCH_HAS_CC_PLATFORM
select KVM_GENERIC_PRIVATE_MEM
+ select HAVE_KVM_GMEM_PREPARE
help
Provides support for launching Encrypted VMs (SEV) and Encrypted VMs
with Encrypted State (SEV-ES) on AMD processors.
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 518c44296f8d..2bc4aa91cd31 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -4565,3 +4565,101 @@ void sev_handle_rmp_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code)
out_no_trace:
put_page(pfn_to_page(pfn));
}
+
+static bool is_pfn_range_shared(kvm_pfn_t start, kvm_pfn_t end)
+{
+ kvm_pfn_t pfn = start;
+
+ while (pfn < end) {
+ int ret, rmp_level;
+ bool assigned;
+
+ ret = snp_lookup_rmpentry(pfn, &assigned, &rmp_level);
+ if (ret) {
+ pr_warn_ratelimited("SEV: Failed to retrieve RMP entry: PFN 0x%llx GFN start 0x%llx GFN end 0x%llx RMP level %d error %d\n",
+ pfn, start, end, rmp_level, ret);
+ return false;
+ }
+
+ if (assigned) {
+ pr_debug("%s: overlap detected, PFN 0x%llx start 0x%llx end 0x%llx RMP level %d\n",
+ __func__, pfn, start, end, rmp_level);
+ return false;
+ }
+
+ pfn++;
+ }
+
+ return true;
+}
+
+static u8 max_level_for_order(int order)
+{
+ if (order >= KVM_HPAGE_GFN_SHIFT(PG_LEVEL_2M))
+ return PG_LEVEL_2M;
+
+ return PG_LEVEL_4K;
+}
+
+static bool is_large_rmp_possible(struct kvm *kvm, kvm_pfn_t pfn, int order)
+{
+ kvm_pfn_t pfn_aligned = ALIGN_DOWN(pfn, PTRS_PER_PMD);
+
+ /*
+ * If this is a large folio, and the entire 2M range containing the
+ * PFN is currently shared, then the entire 2M-aligned range can be
+ * set to private via a single 2M RMP entry.
+ */
+ if (max_level_for_order(order) > PG_LEVEL_4K &&
+ is_pfn_range_shared(pfn_aligned, pfn_aligned + PTRS_PER_PMD))
+ return true;
+
+ return false;
+}
+
+int sev_gmem_prepare(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order)
+{
+ struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+ kvm_pfn_t pfn_aligned;
+ gfn_t gfn_aligned;
+ int level, rc;
+ bool assigned;
+
+ if (!sev_snp_guest(kvm))
+ return 0;
+
+ rc = snp_lookup_rmpentry(pfn, &assigned, &level);
+ if (rc) {
+ pr_err_ratelimited("SEV: Failed to look up RMP entry: GFN %llx PFN %llx error %d\n",
+ gfn, pfn, rc);
+ return -ENOENT;
+ }
+
+ if (assigned) {
+ pr_debug("%s: already assigned: gfn %llx pfn %llx max_order %d level %d\n",
+ __func__, gfn, pfn, max_order, level);
+ return 0;
+ }
+
+ if (is_large_rmp_possible(kvm, pfn, max_order)) {
+ level = PG_LEVEL_2M;
+ pfn_aligned = ALIGN_DOWN(pfn, PTRS_PER_PMD);
+ gfn_aligned = ALIGN_DOWN(gfn, PTRS_PER_PMD);
+ } else {
+ level = PG_LEVEL_4K;
+ pfn_aligned = pfn;
+ gfn_aligned = gfn;
+ }
+
+ rc = rmp_make_private(pfn_aligned, gfn_to_gpa(gfn_aligned), level, sev->asid, false);
+ if (rc) {
+ pr_err_ratelimited("SEV: Failed to update RMP entry: GFN %llx PFN %llx level %d error %d\n",
+ gfn, pfn, level, rc);
+ return -EINVAL;
+ }
+
+ pr_debug("%s: updated: gfn %llx pfn %llx pfn_aligned %llx max_order %d level %d\n",
+ __func__, gfn, pfn, pfn_aligned, max_order, level);
+
+ return 0;
+}
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 546656606b44..b9ecc06f8934 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -5081,6 +5081,8 @@ 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,
+
+ .gmem_prepare = sev_gmem_prepare,
};
/*
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 926bfce571a6..4203bd9012e9 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -736,6 +736,7 @@ extern unsigned int max_sev_asid;
void sev_handle_rmp_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code);
void sev_vcpu_unblocking(struct kvm_vcpu *vcpu);
void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu);
+int sev_gmem_prepare(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order);
#else
static inline struct page *snp_safe_alloc_page(struct kvm_vcpu *vcpu) {
return alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
@@ -752,6 +753,10 @@ static inline int sev_dev_get_attr(u32 group, u64 attr, u64 *val) { return -ENXI
static inline void sev_handle_rmp_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code) {}
static inline void sev_vcpu_unblocking(struct kvm_vcpu *vcpu) {}
static inline void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu) {}
+static inline int sev_gmem_prepare(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order)
+{
+ return 0;
+}
#endif
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 62a0474e1346..f82a137640d8 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -13617,6 +13617,11 @@ bool kvm_arch_no_poll(struct kvm_vcpu *vcpu)
EXPORT_SYMBOL_GPL(kvm_arch_no_poll);
#ifdef CONFIG_HAVE_KVM_GMEM_PREPARE
+bool kvm_arch_gmem_prepare_needed(struct kvm *kvm)
+{
+ return kvm->arch.vm_type == KVM_X86_SNP_VM;
+}
+
int kvm_arch_gmem_prepare(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int max_order)
{
return static_call(kvm_x86_gmem_prepare)(kvm, pfn, gfn, max_order);
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index dfe50c64a552..9714add38852 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -39,8 +39,8 @@ static int kvm_gmem_prepare_folio(struct inode *inode, pgoff_t index, struct fol
gfn = slot->base_gfn + index - slot->gmem.pgoff;
rc = kvm_arch_gmem_prepare(kvm, gfn, pfn, compound_order(compound_head(page)));
if (rc) {
- pr_warn_ratelimited("gmem: Failed to prepare folio for index %lx, error %d.\n",
- index, rc);
+ pr_warn_ratelimited("gmem: Failed to prepare folio for index %lx GFN %llx PFN %llx error %d.\n",
+ index, gfn, pfn, rc);
return rc;
}
}
--
2.25.1
next prev parent reply other threads:[~2024-05-10 21:18 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-10 21:10 [PULL 00/19] KVM: Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Michael Roth
2024-05-10 21:10 ` [PULL 01/19] KVM: MMU: Disable fast path if KVM_EXIT_MEMORY_FAULT is needed Michael Roth
2024-05-10 21:10 ` [PULL 02/19] KVM: SEV: Select KVM_GENERIC_PRIVATE_MEM when CONFIG_KVM_AMD_SEV=y Michael Roth
2024-05-10 21:10 ` [PULL 03/19] KVM: SEV: Add initial SEV-SNP support Michael Roth
2024-05-10 21:10 ` [PULL 04/19] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_START command Michael Roth
2024-05-10 21:10 ` [PULL 05/19] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_UPDATE command Michael Roth
2024-05-10 21:10 ` [PULL 06/19] KVM: SEV: Add KVM_SEV_SNP_LAUNCH_FINISH command Michael Roth
2024-05-10 21:10 ` [PULL 07/19] KVM: SEV: Add support to handle GHCB GPA register VMGEXIT Michael Roth
2024-05-10 21:10 ` [PULL 08/19] KVM: SEV: Add support to handle MSR based Page State Change VMGEXIT Michael Roth
2024-05-10 21:10 ` [PULL 09/19] KVM: SEV: Add support to handle " Michael Roth
2024-05-12 2:06 ` Michael Roth
2024-05-10 21:10 ` [PULL 10/19] KVM: SEV: Add support to handle RMP nested page faults Michael Roth
2024-05-10 21:10 ` [PULL 11/19] KVM: SEV: Support SEV-SNP AP Creation NAE event Michael Roth
2024-05-10 21:10 ` Michael Roth [this message]
2024-05-10 21:10 ` [PULL 13/19] KVM: SEV: Implement gmem hook for invalidating private pages Michael Roth
2024-05-15 22:32 ` Sean Christopherson
2024-05-16 3:11 ` Michael Roth
2024-05-21 16:55 ` Paolo Bonzini
2024-05-16 12:45 ` Paolo Bonzini
2024-05-10 21:10 ` [PULL 14/19] KVM: x86: Implement hook for determining max NPT mapping level Michael Roth
2024-05-10 21:10 ` [PULL 15/19] KVM: SEV: Avoid WBINVD for HVA-based MMU notifications for SNP Michael Roth
2024-05-10 21:10 ` [PULL 16/19] KVM: SVM: Add module parameter to enable SEV-SNP Michael Roth
2024-05-10 21:10 ` [PULL 17/19] KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event Michael Roth
2024-05-17 20:41 ` Edgecombe, Rick P
2024-05-17 22:01 ` Paolo Bonzini
2024-05-18 15:04 ` [PATCH] KVM: SEV: Fix guest memory leak when handling guest requests Michael Roth
2024-05-20 14:17 ` Sean Christopherson
2024-05-20 22:50 ` Michael Roth
2024-05-20 23:32 ` Sean Christopherson
2024-05-21 2:00 ` Michael Roth
2024-05-21 14:09 ` Sean Christopherson
2024-05-21 15:34 ` Michael Roth
2024-05-21 16:58 ` Sean Christopherson
2024-05-21 21:00 ` Michael Roth
2024-05-20 23:02 ` [PATCH v2] " Michael Roth
2024-05-10 21:10 ` [PULL 18/19] KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST NAE event Michael Roth
2024-05-13 15:19 ` Nathan Chancellor
2024-05-13 16:53 ` Paolo Bonzini
2024-05-13 17:05 ` Michael Roth
2024-05-13 17:20 ` Paolo Bonzini
2024-05-13 21:18 ` Michael Roth
2024-05-10 21:10 ` [PULL 19/19] crypto: ccp: Add the SNP_VLEK_LOAD command Michael Roth
2024-05-12 7:14 ` [PULL 00/19] KVM: Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Paolo Bonzini
2024-05-12 8:17 ` Paolo Bonzini
2024-05-13 1:06 ` Michael Roth
2024-05-13 22:08 ` Sean Christopherson
2024-05-31 3:22 ` Michael Roth
2024-06-03 16:44 ` Paolo Bonzini
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