From: Vishal Annapurve <vannapurve@google.com>
To: x86@kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org
Cc: pbonzini@redhat.com, vkuznets@redhat.com, wanpengli@tencent.com,
jmattson@google.com, joro@8bytes.org, tglx@linutronix.de,
mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
hpa@zytor.com, shauh@kernel.org, yang.zhong@intel.com,
drjones@redhat.com, ricarkol@google.com, aaronlewis@google.com,
wei.w.wang@intel.com, kirill.shutemov@linux.intel.com,
corbet@lwn.net, hughd@google.com, jlayton@kernel.org,
bfields@fieldses.org, akpm@linux-foundation.org,
chao.p.peng@linux.intel.com, yu.c.zhang@linux.intel.com,
jun.nakajima@intel.com, dave.hansen@intel.com,
michael.roth@amd.com, qperret@google.com, steven.price@arm.com,
ak@linux.intel.com, david@redhat.com, luto@kernel.org,
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pgonda@google.com, seanjc@google.com, diviness@google.com,
Vishal Annapurve <vannapurve@google.com>
Subject: [RFC V1 PATCH 1/5] x86: kvm: HACK: Allow testing of priv memfd approach
Date: Fri, 8 Apr 2022 21:05:41 +0000 [thread overview]
Message-ID: <20220408210545.3915712-2-vannapurve@google.com> (raw)
In-Reply-To: <20220408210545.3915712-1-vannapurve@google.com>
Add plumbing in KVM logic to allow private memfd series:
https://lore.kernel.org/linux-mm/20220310140911.50924-1-chao.p.peng@linux.intel.com/
to be tested with non-confidential VMs.
1) Existing hypercall KVM_HC_MAP_GPA_RANGE is modified to support
marking pages of the guest memory as privately accessed or
accessed in a shared fashion.
2) kvm_vcpu_is_private_gfn is defined to allow guest accesses to
be categorized as shared or private based on the values set by
KVM_HC_MAP_GPA_RANGE hypercall.
3) KVM_MEM_PRIVATE flag for memslots is marked as always supported.
Signed-off-by: Vishal Annapurve <vannapurve@google.com>
---
arch/x86/include/uapi/asm/kvm_para.h | 1 +
arch/x86/kvm/mmu/mmu.c | 9 +++++----
arch/x86/kvm/x86.c | 16 ++++++++++++++--
include/linux/kvm_host.h | 3 +++
virt/kvm/kvm_main.c | 2 +-
5 files changed, 24 insertions(+), 7 deletions(-)
diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h
index 6e64b27b2c1e..3bc9add4095d 100644
--- a/arch/x86/include/uapi/asm/kvm_para.h
+++ b/arch/x86/include/uapi/asm/kvm_para.h
@@ -102,6 +102,7 @@ struct kvm_clock_pairing {
#define KVM_MAP_GPA_RANGE_PAGE_SZ_2M (1 << 0)
#define KVM_MAP_GPA_RANGE_PAGE_SZ_1G (1 << 1)
#define KVM_MAP_GPA_RANGE_ENC_STAT(n) (n << 4)
+#define KVM_MARK_GPA_RANGE_ENC_ACCESS (1 << 8)
#define KVM_MAP_GPA_RANGE_ENCRYPTED KVM_MAP_GPA_RANGE_ENC_STAT(1)
#define KVM_MAP_GPA_RANGE_DECRYPTED KVM_MAP_GPA_RANGE_ENC_STAT(0)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index b1a30a751db0..ee9bc36011de 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3895,10 +3895,11 @@ static bool kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
static bool kvm_vcpu_is_private_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
{
- /*
- * At this time private gfn has not been supported yet. Other patch
- * that enables it should change this.
- */
+ gpa_t priv_gfn_end = vcpu->priv_gfn + vcpu->priv_pages;
+
+ if ((gfn >= vcpu->priv_gfn) && (gfn < priv_gfn_end))
+ return true;
+
return false;
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 11a949928a85..3b17fa7f2192 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9186,8 +9186,20 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
if (!(vcpu->kvm->arch.hypercall_exit_enabled & (1 << KVM_HC_MAP_GPA_RANGE)))
break;
- if (!PAGE_ALIGNED(gpa) || !npages ||
- gpa_to_gfn(gpa) + npages <= gpa_to_gfn(gpa)) {
+ if (!PAGE_ALIGNED(gpa) ||
+ gpa_to_gfn(gpa) + npages < gpa_to_gfn(gpa)) {
+ ret = -KVM_EINVAL;
+ break;
+ }
+
+ if (attrs & KVM_MARK_GPA_RANGE_ENC_ACCESS) {
+ vcpu->priv_gfn = gpa_to_gfn(gpa);
+ vcpu->priv_pages = npages;
+ ret = 0;
+ break;
+ }
+
+ if (!npages) {
ret = -KVM_EINVAL;
break;
}
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 0150e952a131..7c12a0bdb495 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -311,6 +311,9 @@ struct kvm_vcpu {
u64 requests;
unsigned long guest_debug;
+ uint64_t priv_gfn;
+ uint64_t priv_pages;
+
struct mutex mutex;
struct kvm_run *run;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index df5311755a40..a31a58aa1b79 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1487,7 +1487,7 @@ static void kvm_replace_memslot(struct kvm *kvm,
bool __weak kvm_arch_private_memory_supported(struct kvm *kvm)
{
- return false;
+ return true;
}
static int check_memory_region_flags(struct kvm *kvm,
--
2.35.1.1178.g4f1659d476-goog
next prev parent reply other threads:[~2022-04-08 21:06 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-08 21:05 [RFC V1 PATCH 0/5] selftests: KVM: selftests for fd-based approach of supporting private memory Vishal Annapurve
2022-04-08 21:05 ` Vishal Annapurve [this message]
2022-04-08 21:05 ` [RFC V1 PATCH 2/5] selftests: kvm: Fix inline assembly for hypercall Vishal Annapurve
2022-04-08 21:05 ` [RFC V1 PATCH 3/5] selftests: kvm: Add a basic selftest to test private memory Vishal Annapurve
2022-04-08 21:05 ` [RFC V1 PATCH 4/5] selftests: kvm: priv_memfd_test: Add support for memory conversion Vishal Annapurve
2022-04-08 21:05 ` [RFC V1 PATCH 5/5] selftests: kvm: priv_memfd_test: Add shared access test Vishal Annapurve
2022-04-11 12:01 ` [RFC V1 PATCH 0/5] selftests: KVM: selftests for fd-based approach of supporting private memory Nikunj A. Dadhania
2022-04-12 8:25 ` Chao Peng
2022-04-13 0:16 ` Andy Lutomirski
2022-04-13 13:42 ` Michael Roth
2022-04-14 10:07 ` Chao Peng
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