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KVM: arm64: Introduce hyp_alloc_private_va_range()

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hyp_alloc_private_va_range() can be used to reserve private VA ranges
in the nVHE hypervisor. Allocations are aligned based on the order of
the requested size.

This will be used to implement stack guard pages for KVM nVHE hypervisor
(nVHE Hyp mode / not pKVM), in a subsequent patch in the series.

Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220420214317.3303360-2-kaleshsingh@google.com
This commit is contained in:
Kalesh Singh 2022-04-20 14:42:52 -07:00 • committed by Marc Zyngier
parent b2d229d4dd
commit 92abe0f81e
2 changed files with 46 additions and 23 deletions
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1
arch/arm64/include/asm/kvm_mmu.h
View file

@ -154,6 +154,7 @@ static __always_inline unsigned long __kern_hyp_va(unsigned long v)
int kvm_share_hyp(void *from, void *to);
void kvm_unshare_hyp(void *from, void *to);
int create_hyp_mappings(void *from, void *to, enum kvm_pgtable_prot prot);
int hyp_alloc_private_va_range(size_t size, unsigned long *haddr);
int create_hyp_io_mappings(phys_addr_t phys_addr, size_t size,
void __iomem **kaddr,
void __iomem **haddr);

68
arch/arm64/kvm/mmu.c
View file

@ -457,23 +457,22 @@ int create_hyp_mappings(void *from, void *to, enum kvm_pgtable_prot prot)
return 0;
}
static int __create_hyp_private_mapping(phys_addr_t phys_addr, size_t size,
unsigned long *haddr,
enum kvm_pgtable_prot prot)
/**
* hyp_alloc_private_va_range - Allocates a private VA range.
* @size: The size of the VA range to reserve.
* @haddr: The hypervisor virtual start address of the allocation.
*
* The private virtual address (VA) range is allocated below io_map_base
* and aligned based on the order of @size.
*
* Return: 0 on success or negative error code on failure.
*/
int hyp_alloc_private_va_range(size_t size, unsigned long *haddr)
{
unsigned long base;
int ret = 0;
if (!kvm_host_owns_hyp_mappings()) {
base = kvm_call_hyp_nvhe(__pkvm_create_private_mapping,
phys_addr, size, prot);
if (IS_ERR_OR_NULL((void *)base))
return PTR_ERR((void *)base);
*haddr = base;
return 0;
}
mutex_lock(&kvm_hyp_pgd_mutex);
/*
@ -484,8 +483,10 @@ static int __create_hyp_private_mapping(phys_addr_t phys_addr, size_t size,
*
* The allocated size is always a multiple of PAGE_SIZE.
*/
size = PAGE_ALIGN(size + offset_in_page(phys_addr));
base = io_map_base - size;
base = io_map_base - PAGE_ALIGN(size);
/* Align the allocation based on the order of its size */
base = ALIGN_DOWN(base, PAGE_SIZE << get_order(size));
/*
* Verify that BIT(VA_BITS - 1) hasn't been flipped by
@ -495,19 +496,40 @@ static int __create_hyp_private_mapping(phys_addr_t phys_addr, size_t size,
if ((base ^ io_map_base) & BIT(VA_BITS - 1))
ret = -ENOMEM;
else
io_map_base = base;
*haddr = io_map_base = base;
mutex_unlock(&kvm_hyp_pgd_mutex);
if (ret)
goto out;
return ret;
}
ret = __create_hyp_mappings(base, size, phys_addr, prot);
if (ret)
goto out;
static int __create_hyp_private_mapping(phys_addr_t phys_addr, size_t size,
unsigned long *haddr,
enum kvm_pgtable_prot prot)
{
unsigned long addr;
int ret = 0;
*haddr = base + offset_in_page(phys_addr);
out:
if (!kvm_host_owns_hyp_mappings()) {
addr = kvm_call_hyp_nvhe(__pkvm_create_private_mapping,
phys_addr, size, prot);
if (IS_ERR_VALUE(addr))
return addr;
*haddr = addr;
return 0;
}
size = PAGE_ALIGN(size + offset_in_page(phys_addr));
ret = hyp_alloc_private_va_range(size, &addr);
if (ret)
return ret;
ret = __create_hyp_mappings(addr, size, phys_addr, prot);
if (ret)
return ret;
*haddr = addr + offset_in_page(phys_addr);
return ret;
}