Should a guest desire to enroll into the MMIO guard, allow it to
do so with a command-line option.
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
.../admin-guide/kernel-parameters.txt | 3 ++
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/hypervisor.h | 1 +
arch/arm64/kernel/setup.c | 6 +++
arch/arm64/mm/ioremap.c | 38 +++++++++++++++++++
5 files changed, 49 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 91ba391f9b32..62bb25b412a7 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2076,6 +2076,9 @@
1 - Bypass the IOMMU for DMA.
unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
+ ioremap_guard [ARM64] enable the KVM MMIO guard functionality
+ if available.
+
io7= [HW] IO7 for Marvel-based Alpha systems
See comment before marvel_specify_io7 in
arch/alpha/kernel/core_marvel.c.
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 5c7ae4c3954b..4982d21d3c47 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -25,6 +25,7 @@ config ARM64
select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_GIGANTIC_PAGE
+ select ARCH_HAS_IOREMAP_PHYS_HOOKS
select ARCH_HAS_KCOV
select ARCH_HAS_KEEPINITRD
select ARCH_HAS_MEMBARRIER_SYNC_CORE
diff --git a/arch/arm64/include/asm/hypervisor.h b/arch/arm64/include/asm/hypervisor.h
index 8e77f411903f..b130c7b82eaa 100644
--- a/arch/arm64/include/asm/hypervisor.h
+++ b/arch/arm64/include/asm/hypervisor.h
@@ -7,5 +7,6 @@
void kvm_init_hyp_services(void);
bool kvm_arm_hyp_service_available(u32 func_id);
void kvm_arm_init_hyp_services(void);
+void kvm_init_ioremap_services(void);
#endif
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index be5f85b0a24d..c325647f675f 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -49,6 +49,7 @@
#include <asm/tlbflush.h>
#include <asm/traps.h>
#include <asm/efi.h>
+#include <asm/hypervisor.h>
#include <asm/xen/hypervisor.h>
#include <asm/mmu_context.h>
@@ -445,3 +446,8 @@ static int __init register_arm64_panic_block(void)
return 0;
}
device_initcall(register_arm64_panic_block);
+
+void kvm_arm_init_hyp_services(void)
+{
+ kvm_init_ioremap_services();
+}
diff --git a/arch/arm64/mm/ioremap.c b/arch/arm64/mm/ioremap.c
index 5334cbdc9f64..62b715ea31e5 100644
--- a/arch/arm64/mm/ioremap.c
+++ b/arch/arm64/mm/ioremap.c
@@ -30,6 +30,44 @@ static DEFINE_STATIC_KEY_FALSE(ioremap_guard_key);
static DEFINE_XARRAY(ioremap_guard_array);
static DEFINE_MUTEX(ioremap_guard_lock);
+static bool ioremap_guard;
+static int __init ioremap_guard_setup(char *str)
+{
+ ioremap_guard = true;
+
+ return 0;
+}
+early_param("ioremap_guard", ioremap_guard_setup);
+
+void kvm_init_ioremap_services(void)
+{
+ struct arm_smccc_res res;
+
+ if (!ioremap_guard)
+ return;
+
+ /* We need all the functions to be implemented */
+ if (!kvm_arm_hyp_service_available(ARM_SMCCC_KVM_FUNC_MMIO_GUARD_INFO) ||
+ !kvm_arm_hyp_service_available(ARM_SMCCC_KVM_FUNC_MMIO_GUARD_ENROLL) ||
+ !kvm_arm_hyp_service_available(ARM_SMCCC_KVM_FUNC_MMIO_GUARD_MAP) ||
+ !kvm_arm_hyp_service_available(ARM_SMCCC_KVM_FUNC_MMIO_GUARD_UNMAP))
+ return;
+
+ arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_MMIO_GUARD_INFO_FUNC_ID,
+ &res);
+ if (res.a0 != PAGE_SIZE)
+ return;
+
+ arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_MMIO_GUARD_ENROLL_FUNC_ID,
+ &res);
+ if (res.a0 == SMCCC_RET_SUCCESS) {
+ static_branch_enable(&ioremap_guard_key);
+ pr_info("Using KVM MMIO guard for ioremap\n");
+ } else {
+ pr_warn("KVM MMIO guard registration failed (%ld)\n", res.a0);
+ }
+}
+
void ioremap_phys_range_hook(phys_addr_t phys_addr, size_t size, pgprot_t prot)
{
if (!static_branch_unlikely(&ioremap_guard_key))
--
2.30.2
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