From: Andre Przywara <andre.przywara@arm.com>
To: Will Deacon <will@kernel.org>,
Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: kvm@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>,
Raphael Gault <raphael.gault@arm.com>,
Sami Mujawar <sami.mujawar@arm.com>,
kvmarm@lists.cs.columbia.edu
Subject: [PATCH kvmtool v4 4/5] memslot: Add support for READONLY mappings
Date: Thu, 23 Apr 2020 18:38:43 +0100 [thread overview]
Message-ID: <20200423173844.24220-5-andre.przywara@arm.com> (raw)
In-Reply-To: <20200423173844.24220-1-andre.przywara@arm.com>
A KVM memslot has a flags field, which allows to mark a region as
read-only.
Add another memory type bit to allow kvmtool-internal users to map a
write-protected region. Write access would trap and can be handled by
the MMIO emulation, which should register on the same guest address
region.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
include/kvm/kvm.h | 12 ++++++++----
kvm.c | 5 +++++
2 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/include/kvm/kvm.h b/include/kvm/kvm.h
index 9428f57a..53373b08 100644
--- a/include/kvm/kvm.h
+++ b/include/kvm/kvm.h
@@ -40,10 +40,12 @@ enum kvm_mem_type {
KVM_MEM_TYPE_RAM = 1 << 0,
KVM_MEM_TYPE_DEVICE = 1 << 1,
KVM_MEM_TYPE_RESERVED = 1 << 2,
+ KVM_MEM_TYPE_READONLY = 1 << 3,
KVM_MEM_TYPE_ALL = KVM_MEM_TYPE_RAM
| KVM_MEM_TYPE_DEVICE
| KVM_MEM_TYPE_RESERVED
+ | KVM_MEM_TYPE_READONLY
};
struct kvm_ext {
@@ -158,17 +160,19 @@ u64 host_to_guest_flat(struct kvm *kvm, void *ptr);
bool kvm__arch_load_kernel_image(struct kvm *kvm, int fd_kernel, int fd_initrd,
const char *kernel_cmdline);
+#define add_read_only(type, str) \
+ (((type) & KVM_MEM_TYPE_READONLY) ? str " (read-only)" : str)
static inline const char *kvm_mem_type_to_string(enum kvm_mem_type type)
{
- switch (type) {
+ switch (type & ~KVM_MEM_TYPE_READONLY) {
case KVM_MEM_TYPE_ALL:
return "(all)";
case KVM_MEM_TYPE_RAM:
- return "RAM";
+ return add_read_only(type, "RAM");
case KVM_MEM_TYPE_DEVICE:
- return "device";
+ return add_read_only(type, "device");
case KVM_MEM_TYPE_RESERVED:
- return "reserved";
+ return add_read_only(type, "reserved");
}
return "???";
diff --git a/kvm.c b/kvm.c
index 26f6b9bc..e327541d 100644
--- a/kvm.c
+++ b/kvm.c
@@ -242,6 +242,7 @@ int kvm__register_mem(struct kvm *kvm, u64 guest_phys, u64 size,
struct kvm_mem_bank *bank;
struct list_head *prev_entry;
u32 slot;
+ u32 flags = 0;
int ret;
mutex_lock(&kvm->mem_banks_lock);
@@ -313,9 +314,13 @@ int kvm__register_mem(struct kvm *kvm, u64 guest_phys, u64 size,
bank->type = type;
bank->slot = slot;
+ if (type & KVM_MEM_TYPE_READONLY)
+ flags |= KVM_MEM_READONLY;
+
if (type != KVM_MEM_TYPE_RESERVED) {
mem = (struct kvm_userspace_memory_region) {
.slot = slot,
+ .flags = flags,
.guest_phys_addr = guest_phys,
.memory_size = size,
.userspace_addr = (unsigned long)userspace_addr,
--
2.17.1
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next prev parent reply other threads:[~2020-04-23 17:39 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-23 17:38 [PATCH kvmtool v4 0/5] Add CFI flash emulation Andre Przywara
2020-04-23 17:38 ` [PATCH kvmtool v4 1/5] virtio-mmio: Assign IRQ line directly before registering device Andre Przywara
2020-04-24 8:41 ` Will Deacon
2020-04-24 8:50 ` André Przywara
2020-04-24 9:51 ` Will Deacon
2020-04-23 17:38 ` [PATCH kvmtool v4 2/5] Add emulation for CFI compatible flash memory Andre Przywara
2020-04-23 17:38 ` [PATCH kvmtool v4 3/5] vfio: Destroy memslot when unmapping the associated VAs Andre Przywara
2020-04-23 17:38 ` Andre Przywara [this message]
2020-04-24 8:41 ` [PATCH kvmtool v4 4/5] memslot: Add support for READONLY mappings Will Deacon
2020-04-23 17:38 ` [PATCH kvmtool v4 5/5] cfi-flash: Add support for mapping flash into guest Andre Przywara
2020-04-23 17:55 ` [PATCH kvmtool v4 0/5] Add CFI flash emulation Ard Biesheuvel
2020-04-23 20:43 ` Ard Biesheuvel
2020-04-23 21:31 ` André Przywara
2020-04-24 6:45 ` Ard Biesheuvel
2020-04-24 12:08 ` André Przywara
2020-04-24 12:25 ` Ard Biesheuvel
2020-04-24 8:40 ` Will Deacon
2020-04-24 17:03 ` Will Deacon
2020-04-25 15:16 ` Ard Biesheuvel
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