| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <2737fd9776aaa1ff7537244e128083ace0cf2cc8.1760731772.git.ackerleytng@google.com>
Date: Fri, 17 Oct 2025 13:11:45 -0700
From: Ackerley Tng <ackerleytng@...gle.com>
To: cgroups@...r.kernel.org, kvm@...r.kernel.org, linux-doc@...r.kernel.org,
linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-kselftest@...r.kernel.org, linux-mm@...ck.org,
linux-trace-kernel@...r.kernel.org, x86@...nel.org
Cc: ackerleytng@...gle.com, akpm@...ux-foundation.org,
binbin.wu@...ux.intel.com, bp@...en8.de, brauner@...nel.org,
chao.p.peng@...el.com, chenhuacai@...nel.org, corbet@....net,
dave.hansen@...el.com, dave.hansen@...ux.intel.com, david@...hat.com,
dmatlack@...gle.com, erdemaktas@...gle.com, fan.du@...el.com, fvdl@...gle.com,
haibo1.xu@...el.com, hannes@...xchg.org, hch@...radead.org, hpa@...or.com,
hughd@...gle.com, ira.weiny@...el.com, isaku.yamahata@...el.com, jack@...e.cz,
james.morse@....com, jarkko@...nel.org, jgg@...pe.ca, jgowans@...zon.com,
jhubbard@...dia.com, jroedel@...e.de, jthoughton@...gle.com,
jun.miao@...el.com, kai.huang@...el.com, keirf@...gle.com,
kent.overstreet@...ux.dev, liam.merwick@...cle.com,
maciej.wieczor-retman@...el.com, mail@...iej.szmigiero.name,
maobibo@...ngson.cn, mathieu.desnoyers@...icios.com, maz@...nel.org,
mhiramat@...nel.org, mhocko@...nel.org, mic@...ikod.net, michael.roth@....com,
mingo@...hat.com, mlevitsk@...hat.com, mpe@...erman.id.au,
muchun.song@...ux.dev, nikunj@....com, nsaenz@...zon.es,
oliver.upton@...ux.dev, palmer@...belt.com, pankaj.gupta@....com,
paul.walmsley@...ive.com, pbonzini@...hat.com, peterx@...hat.com,
pgonda@...gle.com, prsampat@....com, pvorel@...e.cz, qperret@...gle.com,
richard.weiyang@...il.com, rick.p.edgecombe@...el.com, rientjes@...gle.com,
rostedt@...dmis.org, roypat@...zon.co.uk, rppt@...nel.org, seanjc@...gle.com,
shakeel.butt@...ux.dev, shuah@...nel.org, steven.price@....com,
steven.sistare@...cle.com, suzuki.poulose@....com, tabba@...gle.com,
tglx@...utronix.de, thomas.lendacky@....com, vannapurve@...gle.com,
vbabka@...e.cz, viro@...iv.linux.org.uk, vkuznets@...hat.com,
wei.w.wang@...el.com, will@...nel.org, willy@...radead.org, wyihan@...gle.com,
xiaoyao.li@...el.com, yan.y.zhao@...el.com, yilun.xu@...el.com,
yuzenghui@...wei.com, zhiquan1.li@...el.com
Subject: [RFC PATCH v1 04/37] KVM: Stub in ability to disable per-VM memory
attribute tracking
From: Sean Christopherson <seanjc@...gle.com>
Introduce the basic infrastructure to allow per-VM memory attribute
tracking to be disabled. This will be built-upon in a later patch, where a
module param can disable per-VM memory attribute tracking.
Split the Kconfig option into a base KVM_MEMORY_ATTRIBUTES and the
existing KVM_VM_MEMORY_ATTRIBUTES. The base option provides the core
plumbing, while the latter enables the full per-VM tracking via an xarray
and the associated ioctls.
kvm_get_memory_attributes() now performs a static call that either looks up
kvm->mem_attr_array with CONFIG_KVM_VM_MEMORY_ATTRIBUTES is enabled, or
just returns 0 otherwise. The static call can be patched depending on
whether per-VM tracking is enabled by the CONFIG.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
arch/x86/include/asm/kvm_host.h | 2 +-
include/linux/kvm_host.h | 23 ++++++++++-------
virt/kvm/Kconfig | 6 ++++-
virt/kvm/kvm_main.c | 44 ++++++++++++++++++++++++++++++++-
4 files changed, 63 insertions(+), 12 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index efb0b2e1808d5..197b28ae0e28c 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -2301,7 +2301,7 @@ void kvm_configure_mmu(bool enable_tdp, int tdp_forced_root_level,
int tdp_max_root_level, int tdp_huge_page_level);
-#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
+#ifdef CONFIG_KVM_MEMORY_ATTRIBUTES
#define kvm_arch_has_private_mem(kvm) ((kvm)->arch.has_private_mem)
#endif
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 21bf30e8d3cc1..512febf47c265 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2514,19 +2514,15 @@ static inline bool kvm_memslot_is_gmem_only(const struct kvm_memory_slot *slot)
return slot->flags & KVM_MEMSLOT_GMEM_ONLY;
}
-#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
+#ifdef CONFIG_KVM_MEMORY_ATTRIBUTES
+typedef unsigned long (kvm_get_memory_attributes_t)(struct kvm *kvm, gfn_t gfn);
+DECLARE_STATIC_CALL(__kvm_get_memory_attributes, kvm_get_memory_attributes_t);
+
static inline unsigned long kvm_get_memory_attributes(struct kvm *kvm, gfn_t gfn)
{
- return xa_to_value(xa_load(&kvm->mem_attr_array, gfn));
+ return static_call(__kvm_get_memory_attributes)(kvm, gfn);
}
-bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
- unsigned long mask, unsigned long attrs);
-bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm,
- struct kvm_gfn_range *range);
-bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
- struct kvm_gfn_range *range);
-
static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
{
return kvm_get_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE;
@@ -2536,6 +2532,15 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
{
return false;
}
+#endif
+
+#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
+bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
+ unsigned long mask, unsigned long attrs);
+bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm,
+ struct kvm_gfn_range *range);
+bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
+ struct kvm_gfn_range *range);
#endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
#ifdef CONFIG_KVM_GUEST_MEMFD
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index 9dd7873114b59..395996977fe5a 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -108,10 +108,14 @@ config KVM_MMU_LOCKLESS_AGING
depends on KVM_GENERIC_MMU_NOTIFIER
bool
-config KVM_VM_MEMORY_ATTRIBUTES
+config KVM_MEMORY_ATTRIBUTES
depends on KVM_GENERIC_MMU_NOTIFIER
bool
+config KVM_VM_MEMORY_ATTRIBUTES
+ select KVM_MEMORY_ATTRIBUTES
+ bool
+
config KVM_GUEST_MEMFD
depends on KVM_GENERIC_MMU_NOTIFIER
select XARRAY_MULTI
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 591795a3fa124..6c29770dfa7c8 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -101,6 +101,17 @@ EXPORT_SYMBOL_FOR_KVM_INTERNAL(halt_poll_ns_shrink);
static bool allow_unsafe_mappings;
module_param(allow_unsafe_mappings, bool, 0444);
+#ifdef CONFIG_KVM_MEMORY_ATTRIBUTES
+#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
+static bool vm_memory_attributes = true;
+#else
+#define vm_memory_attributes false
+#endif
+DEFINE_STATIC_CALL_RET0(__kvm_get_memory_attributes, kvm_get_memory_attributes_t);
+EXPORT_SYMBOL_FOR_KVM_INTERNAL(STATIC_CALL_KEY(__kvm_get_memory_attributes));
+EXPORT_SYMBOL_FOR_KVM_INTERNAL(STATIC_CALL_TRAMP(__kvm_get_memory_attributes));
+#endif
+
/*
* Ordering of locks:
*
@@ -2425,7 +2436,7 @@ static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
}
#endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
-#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
+#ifdef CONFIG_KVM_MEMORY_ATTRIBUTES
static u64 kvm_supported_mem_attributes(struct kvm *kvm)
{
#ifdef kvm_arch_has_private_mem
@@ -2436,6 +2447,12 @@ static u64 kvm_supported_mem_attributes(struct kvm *kvm)
return 0;
}
+#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
+static unsigned long kvm_get_vm_memory_attributes(struct kvm *kvm, gfn_t gfn)
+{
+ return xa_to_value(xa_load(&kvm->mem_attr_array, gfn));
+}
+
/*
* Returns true if _all_ gfns in the range [@start, @end) have attributes
* such that the bits in @mask match @attrs.
@@ -2632,7 +2649,24 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
return kvm_vm_set_mem_attributes(kvm, start, end, attrs->attributes);
}
+#else /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
+static unsigned long kvm_get_vm_memory_attributes(struct kvm *kvm, gfn_t gfn)
+{
+ BUILD_BUG_ON(1);
+}
#endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
+static void kvm_init_memory_attributes(void)
+{
+ if (vm_memory_attributes)
+ static_call_update(__kvm_get_memory_attributes,
+ kvm_get_vm_memory_attributes);
+ else
+ static_call_update(__kvm_get_memory_attributes,
+ (void *)__static_call_return0);
+}
+#else /* CONFIG_KVM_MEMORY_ATTRIBUTES */
+static void kvm_init_memory_attributes(void) { }
+#endif /* CONFIG_KVM_MEMORY_ATTRIBUTES */
struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
{
@@ -4925,6 +4959,9 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
return 1;
#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
case KVM_CAP_MEMORY_ATTRIBUTES:
+ if (!vm_memory_attributes)
+ return 0;
+
return kvm_supported_mem_attributes(kvm);
#endif
#ifdef CONFIG_KVM_GUEST_MEMFD
@@ -5331,6 +5368,10 @@ static long kvm_vm_ioctl(struct file *filp,
case KVM_SET_MEMORY_ATTRIBUTES: {
struct kvm_memory_attributes attrs;
+ r = -ENOTTY;
+ if (!vm_memory_attributes)
+ goto out;
+
r = -EFAULT;
if (copy_from_user(&attrs, argp, sizeof(attrs)))
goto out;
@@ -6513,6 +6554,7 @@ int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module)
kvm_preempt_ops.sched_in = kvm_sched_in;
kvm_preempt_ops.sched_out = kvm_sched_out;
+ kvm_init_memory_attributes();
kvm_init_debug();
r = kvm_vfio_ops_init();
--
2.51.0.858.gf9c4a03a3a-goog
Powered by blists - more mailing lists