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arm64: KVM: Dynamically compute the HYP VA mask 

As we're moving towards a much more dynamic way to compute our
HYP VA, let's express the mask in a slightly different way.

Instead of comparing the idmap position to the "low" VA mask,
we directly compute the mask by taking into account the idmap's
(VA_BIT-1) bit.

No functionnal change.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Marc Zyngier 2017-12-08 14:18:27 +00:00
parent 11d764079c
commit 005e975a3b
1 changed files with 6 additions and 11 deletions
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17
arch/arm64/kvm/va_layout.c
View File

@ -21,24 +21,19 @@
#include <asm/insn.h>
#include <asm/kvm_mmu.h>
#define HYP_PAGE_OFFSET_HIGH_MASK ((UL(1) << VA_BITS) - 1)
#define HYP_PAGE_OFFSET_LOW_MASK ((UL(1) << (VA_BITS - 1)) - 1)
static u64 va_mask;
static void compute_layout(void)
{
phys_addr_t idmap_addr = __pa_symbol(__hyp_idmap_text_start);
unsigned long mask = HYP_PAGE_OFFSET_HIGH_MASK;
u64 hyp_va_msb;
/*
* Activate the lower HYP offset only if the idmap doesn't
* clash with it,
*/
if (idmap_addr > HYP_PAGE_OFFSET_LOW_MASK)
mask = HYP_PAGE_OFFSET_LOW_MASK;
/* Where is my RAM region? */
hyp_va_msb = idmap_addr & BIT(VA_BITS - 1);
hyp_va_msb ^= BIT(VA_BITS - 1);
va_mask = mask;
va_mask = GENMASK_ULL(VA_BITS - 2, 0);
va_mask |= hyp_va_msb;
}
static u32 compute_instruction(int n, u32 rd, u32 rn)