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Message-ID: <20231113022326.24388-9-mic@digikod.net>
Date: Sun, 12 Nov 2023 21:23:15 -0500
From: Mickaël Salaün <mic@...ikod.net>
To: Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>,
"H . Peter Anvin" <hpa@...or.com>,
Ingo Molnar <mingo@...hat.com>,
Kees Cook <keescook@...omium.org>,
Paolo Bonzini <pbonzini@...hat.com>,
Sean Christopherson <seanjc@...gle.com>,
Thomas Gleixner <tglx@...utronix.de>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Wanpeng Li <wanpengli@...cent.com>
Cc: Mickaël Salaün <mic@...ikod.net>,
Alexander Graf <graf@...zon.com>,
Chao Peng <chao.p.peng@...ux.intel.com>,
"Edgecombe, Rick P" <rick.p.edgecombe@...el.com>,
Forrest Yuan Yu <yuanyu@...gle.com>,
James Gowans <jgowans@...zon.com>,
James Morris <jamorris@...ux.microsoft.com>,
John Andersen <john.s.andersen@...el.com>,
"Madhavan T . Venkataraman" <madvenka@...ux.microsoft.com>,
Marian Rotariu <marian.c.rotariu@...il.com>,
Mihai Donțu <mdontu@...defender.com>,
Nicușor Cîțu <nicu.citu@...oud.com>,
Thara Gopinath <tgopinath@...rosoft.com>,
Trilok Soni <quic_tsoni@...cinc.com>,
Wei Liu <wei.liu@...nel.org>,
Will Deacon <will@...nel.org>,
Yu Zhang <yu.c.zhang@...ux.intel.com>,
Zahra Tarkhani <ztarkhani@...rosoft.com>,
Ștefan Șicleru <ssicleru@...defender.com>,
dev@...ts.cloudhypervisor.org,
kvm@...r.kernel.org,
linux-hardening@...r.kernel.org,
linux-hyperv@...r.kernel.org,
linux-kernel@...r.kernel.org,
linux-security-module@...r.kernel.org,
qemu-devel@...gnu.org,
virtualization@...ts.linux-foundation.org,
x86@...nel.org,
xen-devel@...ts.xenproject.org
Subject: [RFC PATCH v2 08/19] KVM: x86: Extend kvm_vm_set_mem_attributes() with a mask
Enable to only update a subset of attributes.
This is needed to be able to use the XArray for different use cases and
make sure they don't interfere (see a following commit).
Cc: Chao Peng <chao.p.peng@...ux.intel.com>
Cc: Kees Cook <keescook@...omium.org>
Cc: Madhavan T. Venkataraman <madvenka@...ux.microsoft.com>
Cc: Sean Christopherson <seanjc@...gle.com>
Cc: Yu Zhang <yu.c.zhang@...ux.intel.com>
Signed-off-by: Mickaël Salaün <mic@...ikod.net>
---
Changes since v1:
* New patch
---
arch/x86/kvm/mmu/mmu.c | 2 +-
include/linux/kvm_host.h | 2 +-
virt/kvm/kvm_main.c | 27 +++++++++++++++++++--------
3 files changed, 21 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 4d378d308762..d7010e09440d 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -7283,7 +7283,7 @@ static bool hugepage_has_attrs(struct kvm *kvm, struct kvm_memory_slot *slot,
for (gfn = start; gfn < end; gfn += KVM_PAGES_PER_HPAGE(level - 1)) {
if (hugepage_test_mixed(slot, gfn, level - 1) ||
- attrs != kvm_get_memory_attributes(kvm, gfn))
+ !(attrs & kvm_get_memory_attributes(kvm, gfn)))
return false;
}
return true;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 85b8648fd892..de68390ab0f2 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2397,7 +2397,7 @@ bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm,
bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
struct kvm_gfn_range *range);
int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
- unsigned long attributes);
+ unsigned long attributes, unsigned long mask);
static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
{
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 0096ccfbb609..e2c178db17d5 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2436,7 +2436,7 @@ static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
/*
* Returns true if _all_ gfns in the range [@start, @end) have attributes
- * matching @attrs.
+ * matching the @attrs bitmask.
*/
bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
unsigned long attrs)
@@ -2459,7 +2459,8 @@ bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
entry = xas_next(&xas);
} while (xas_retry(&xas, entry));
- if (xas.xa_index != index || xa_to_value(entry) != attrs) {
+ if (xas.xa_index != index ||
+ (xa_to_value(entry) & attrs) != attrs) {
has_attrs = false;
break;
}
@@ -2553,7 +2554,7 @@ static bool kvm_pre_set_memory_attributes(struct kvm *kvm,
/* Set @attributes for the gfn range [@start, @end). */
int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
- unsigned long attributes)
+ unsigned long attributes, unsigned long mask)
{
struct kvm_mmu_notifier_range pre_set_range = {
.start = start,
@@ -2572,11 +2573,8 @@ int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
.may_block = true,
};
unsigned long i;
- void *entry;
int r = 0;
- entry = attributes ? xa_mk_value(attributes) : NULL;
-
lockdep_assert_held(&kvm->slots_arch_lock);
/* Nothing to do if the entire range as the desired attributes. */
@@ -2596,6 +2594,16 @@ int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
kvm_handle_gfn_range(kvm, &pre_set_range);
for (i = start; i < end; i++) {
+ unsigned long value = 0;
+ void *entry;
+
+ entry = xa_load(&kvm->mem_attr_array, i);
+ if (xa_is_value(entry))
+ value = xa_to_value(entry) & ~mask;
+
+ value |= attributes & mask;
+ entry = value ? xa_mk_value(value) : NULL;
+
r = xa_err(xa_store(&kvm->mem_attr_array, i, entry,
GFP_KERNEL_ACCOUNT));
KVM_BUG_ON(r, kvm);
@@ -2609,12 +2617,14 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
struct kvm_memory_attributes *attrs)
{
int r;
+ unsigned long attrs_mask;
gfn_t start, end;
/* flags is currently not used. */
if (attrs->flags)
return -EINVAL;
- if (attrs->attributes & ~kvm_supported_mem_attributes(kvm))
+ attrs_mask = kvm_supported_mem_attributes(kvm);
+ if (attrs->attributes & ~attrs_mask)
return -EINVAL;
if (attrs->size == 0 || attrs->address + attrs->size < attrs->address)
return -EINVAL;
@@ -2632,7 +2642,8 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
BUILD_BUG_ON(sizeof(attrs->attributes) != sizeof(unsigned long));
mutex_lock(&kvm->slots_arch_lock);
- r = kvm_vm_set_mem_attributes(kvm, start, end, attrs->attributes);
+ r = kvm_vm_set_mem_attributes(kvm, start, end, attrs->attributes,
+ attrs_mask);
mutex_unlock(&kvm->slots_arch_lock);
return r;
}
--
2.42.1
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