Thread (6 messages) 6 messages, 3 authors, 2021-08-20

Re: [PATCH 1/2] KVM: arm64: Fix off-by-one in range_is_memory

From: Quentin Perret <hidden>
Date: 2021-07-29 16:52:57
Also in: kvmarm, lkml

On Wednesday 28 Jul 2021 at 15:32:31 (+0000), David Brazdil wrote:
quoted hunk ↗ jump to hunk
Hyp checks whether an address range only covers RAM by checking the
start/endpoints against a list of memblock_region structs. However,
the endpoint here is exclusive but internally is treated as inclusive.
Fix the off-by-one error that caused valid address ranges to be
rejected.

Cc: Quentin Perret <redacted>
Fixes: 90134ac9cabb6 ("KVM: arm64: Protect the .hyp sections from the host")
Signed-off-by: David Brazdil <redacted>
---
 arch/arm64/kvm/hyp/nvhe/mem_protect.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index d938ce95d3bd..a6ce991b1467 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -193,7 +193,7 @@ static bool range_is_memory(u64 start, u64 end)
 {
 	struct kvm_mem_range r1, r2;
 
-	if (!find_mem_range(start, &r1) || !find_mem_range(end, &r2))
+	if (!find_mem_range(start, &r1) || !find_mem_range(end - 1, &r2))
 		return false;
 	if (r1.start != r2.start)
 		return false;
Looks good to me:

Reviewed-by: Quentin Perret <redacted>

Thanks,
Quentin

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