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FROMLIST: KVM: arm64: Introduce KVM_PGTABLE_S2_NOFWB Stage-2 flag

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In order to further configure stage-2 page-tables, pass flags to the
init function using a new enum.

The first of these flags allows to disable FWB even if the hardware
supports it as we will need to do so for the host stage-2.

Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20210317141714.383046-2-qperret@google.com
Bug: 178098380
Change-Id: I19441d59f5bd31f6ffbefbab06c7377e29ad3246
This commit is contained in:
Quentin Perret
2021-03-17 14:17:13 +00:00
parent bcdcab0253
commit 3a16a9e7be
3 changed files with 50 additions and 22 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
arch/arm64/include/asm/kvm_pgtable.h
View File

@@ -56,6 +56,15 @@ struct kvm_pgtable_mm_ops {
phys_addr_t (*virt_to_phys)(void *addr);
};
/**
* enum kvm_pgtable_stage2_flags - Stage-2 page-table flags.
* @KVM_PGTABLE_S2_NOFWB: Don't enforce Normal-WB even if the CPUs have
* ARM64_HAS_STAGE2_FWB.
*/
enum kvm_pgtable_stage2_flags {
KVM_PGTABLE_S2_NOFWB = BIT(0),
};
/**
* struct kvm_pgtable - KVM page-table.
* @ia_bits: Maximum input address size, in bits.
@@ -72,6 +81,7 @@ struct kvm_pgtable {
/* Stage-2 only */
struct kvm_s2_mmu *mmu;
enum kvm_pgtable_stage2_flags flags;
};
/**
@@ -201,11 +211,16 @@ u64 kvm_get_vtcr(u64 mmfr0, u64 mmfr1, u32 phys_shift);
* @arch: Arch-specific KVM structure representing the guest virtual
* machine.
* @mm_ops: Memory management callbacks.
* @flags: Stage-2 configuration flags.
*
* Return: 0 on success, negative error code on failure.
*/
int kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_arch *arch,
struct kvm_pgtable_mm_ops *mm_ops);
int kvm_pgtable_stage2_init_flags(struct kvm_pgtable *pgt, struct kvm_arch *arch,
struct kvm_pgtable_mm_ops *mm_ops,
enum kvm_pgtable_stage2_flags flags);
#define kvm_pgtable_stage2_init(pgt, arch, mm_ops) \
kvm_pgtable_stage2_init_flags(pgt, arch, mm_ops, 0)
/**
* kvm_pgtable_stage2_destroy() - Destroy an unused guest stage-2 page-table.

4
arch/arm64/include/asm/pgtable-prot.h
View File

@@ -71,10 +71,10 @@ extern bool arm64_use_ng_mappings;
#define PAGE_KERNEL_EXEC __pgprot(PROT_NORMAL & ~PTE_PXN)
#define PAGE_KERNEL_EXEC_CONT __pgprot((PROT_NORMAL & ~PTE_PXN) | PTE_CONT)
#define PAGE_S2_MEMATTR(attr) \
#define PAGE_S2_MEMATTR(attr, has_fwb) \
({ \
u64 __val; \
if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) \
if (has_fwb) \
__val = PTE_S2_MEMATTR(MT_S2_FWB_ ## attr); \
else \
__val = PTE_S2_MEMATTR(MT_S2_ ## attr); \

49
arch/arm64/kvm/hyp/pgtable.c
View File

@@ -508,12 +508,25 @@ u64 kvm_get_vtcr(u64 mmfr0, u64 mmfr1, u32 phys_shift)
return vtcr;
}
static int stage2_set_prot_attr(enum kvm_pgtable_prot prot, kvm_pte_t *ptep)
static bool stage2_has_fwb(struct kvm_pgtable *pgt)
{
if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB))
return false;
return !(pgt->flags & KVM_PGTABLE_S2_NOFWB);
}
static int stage2_set_prot_attr(enum kvm_pgtable_prot prot, kvm_pte_t *ptep,
struct kvm_pgtable *pgt)
{
bool device = prot & KVM_PGTABLE_PROT_DEVICE;
kvm_pte_t attr = device ? PAGE_S2_MEMATTR(DEVICE_nGnRE) :
PAGE_S2_MEMATTR(NORMAL);
u32 sh = KVM_PTE_LEAF_ATTR_LO_S2_SH_IS;
kvm_pte_t attr;
if (device)
attr = PAGE_S2_MEMATTR(DEVICE_nGnRE, stage2_has_fwb(pgt));
else
attr = PAGE_S2_MEMATTR(NORMAL, stage2_has_fwb(pgt));
if (!(prot & KVM_PGTABLE_PROT_X))
attr |= KVM_PTE_LEAF_ATTR_HI_S2_XN;
@@ -749,7 +762,7 @@ int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
.arg = &map_data,
};
ret = stage2_set_prot_attr(prot, &map_data.attr);
ret = stage2_set_prot_attr(prot, &map_data.attr, pgt);
if (ret)
return ret;
@@ -787,16 +800,13 @@ int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *pgt, u64 addr, u64 size,
static void stage2_flush_dcache(void *addr, u64 size)
{
if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB))
return;
__flush_dcache_area(addr, size);
}
static bool stage2_pte_cacheable(kvm_pte_t pte)
static bool stage2_pte_cacheable(kvm_pte_t pte, struct kvm_pgtable *pgt)
{
u64 memattr = pte & KVM_PTE_LEAF_ATTR_LO_S2_MEMATTR;
return memattr == PAGE_S2_MEMATTR(NORMAL);
return memattr == PAGE_S2_MEMATTR(NORMAL, stage2_has_fwb(pgt));
}
static int stage2_unmap_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
@@ -822,8 +832,8 @@ static int stage2_unmap_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
if (mm_ops->page_count(childp) != 1)
return 0;
} else if (stage2_pte_cacheable(pte)) {
need_flush = true;
} else if (stage2_pte_cacheable(pte, pgt)) {
need_flush = !stage2_has_fwb(pgt);
}
/*
@@ -980,10 +990,11 @@ static int stage2_flush_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
enum kvm_pgtable_walk_flags flag,
void * const arg)
{
struct kvm_pgtable_mm_ops *mm_ops = arg;
struct kvm_pgtable *pgt = arg;
struct kvm_pgtable_mm_ops *mm_ops = pgt->mm_ops;
kvm_pte_t pte = *ptep;
if (!kvm_pte_valid(pte) || !stage2_pte_cacheable(pte))
if (!kvm_pte_valid(pte) || !stage2_pte_cacheable(pte, pgt))
return 0;
stage2_flush_dcache(kvm_pte_follow(pte, mm_ops), kvm_granule_size(level));
@@ -995,17 +1006,18 @@ int kvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size)
struct kvm_pgtable_walker walker = {
.cb = stage2_flush_walker,
.flags = KVM_PGTABLE_WALK_LEAF,
.arg = pgt->mm_ops,
.arg = pgt,
};
if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB))
if (stage2_has_fwb(pgt))
return 0;
return kvm_pgtable_walk(pgt, addr, size, &walker);
}
int kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_arch *arch,
struct kvm_pgtable_mm_ops *mm_ops)
int kvm_pgtable_stage2_init_flags(struct kvm_pgtable *pgt, struct kvm_arch *arch,
struct kvm_pgtable_mm_ops *mm_ops,
enum kvm_pgtable_stage2_flags flags)
{
size_t pgd_sz;
u64 vtcr = arch->vtcr;
@@ -1018,6 +1030,7 @@ int kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_arch *arch,
if (!pgt->pgd)
return -ENOMEM;
pgt->flags = flags;
pgt->ia_bits = ia_bits;
pgt->start_level = start_level;
pgt->mm_ops = mm_ops;
@@ -1102,7 +1115,7 @@ int kvm_pgtable_stage2_find_range(struct kvm_pgtable *pgt, u64 addr,
u32 level;
int ret;
ret = stage2_set_prot_attr(prot, &attr);
ret = stage2_set_prot_attr(prot, &attr, pgt);
if (ret)
return ret;
attr &= KVM_PTE_LEAF_S2_COMPAT_MASK;