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ANDROID: BACKPORT: arm64: Enroll into KVM's MMIO guard if required

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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@kernel.org>
Bug: 233587962
Change-Id: Ia9a77f693531740500739693c52b4959abacafd4
[willdeacon@: Add hypercall IDs]
Signed-off-by: Will Deacon <willdeacon@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
This commit is contained in:
Marc Zyngier
2021-09-29 15:39:47 +01:00
committed by Quentin Perret
parent 4c87d6516a
commit f7c4ae96ad
5 changed files with 65 additions and 0 deletions
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3
Documentation/admin-guide/kernel-parameters.txt
View File

@@ -2184,6 +2184,9 @@
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.

1
arch/arm64/Kconfig
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@@ -28,6 +28,7 @@ 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

1
arch/arm64/include/asm/hypervisor.h
View File

@@ -8,5 +8,6 @@ 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_memshare_services(void);
void kvm_init_ioremap_services(void);
#endif

2
arch/arm64/kernel/setup.c
View File

@@ -50,6 +50,7 @@
#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>
@@ -442,5 +443,6 @@ device_initcall(register_arm64_panic_block);
void kvm_arm_init_hyp_services(void)
{
kvm_init_ioremap_services();
kvm_init_memshare_services();
}

58
arch/arm64/mm/ioremap.c
View File

@@ -11,6 +11,26 @@
#include <asm/tlbflush.h>
#include <asm/hypervisor.h>
#ifndef ARM_SMCCC_KVM_FUNC_MMIO_GUARD_INFO
#define ARM_SMCCC_KVM_FUNC_MMIO_GUARD_INFO 5
#define ARM_SMCCC_VENDOR_HYP_KVM_MMIO_GUARD_INFO_FUNC_ID \
ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
ARM_SMCCC_SMC_64, \
ARM_SMCCC_OWNER_VENDOR_HYP, \
ARM_SMCCC_KVM_FUNC_MMIO_GUARD_INFO)
#endif /* ARM_SMCCC_KVM_FUNC_MMIO_GUARD_INFO */
#ifndef ARM_SMCCC_KVM_FUNC_MMIO_GUARD_ENROLL
#define ARM_SMCCC_KVM_FUNC_MMIO_GUARD_ENROLL 6
#define ARM_SMCCC_VENDOR_HYP_KVM_MMIO_GUARD_ENROLL_FUNC_ID \
ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
ARM_SMCCC_SMC_64, \
ARM_SMCCC_OWNER_VENDOR_HYP, \
ARM_SMCCC_KVM_FUNC_MMIO_GUARD_ENROLL)
#endif /* ARM_SMCCC_KVM_FUNC_MMIO_GUARD_ENROLL */
#ifndef ARM_SMCCC_KVM_FUNC_MMIO_GUARD_MAP
#define ARM_SMCCC_KVM_FUNC_MMIO_GUARD_MAP 7
@@ -39,6 +59,44 @@ 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,
0, 0, 0, &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))