* [PATCH] KVM: arm64: Use correct accessor to parse stage-1 PTEs
@ 2022-10-25 14:51 Quentin Perret
2022-10-25 15:30 ` Marc Zyngier
0 siblings, 1 reply; 2+ messages in thread
From: Quentin Perret @ 2022-10-25 14:51 UTC (permalink / raw)
To: Marc Zyngier, James Morse, Alexandru Elisei, Suzuki K Poulose,
Oliver Upton, Catalin Marinas, Will Deacon
Cc: Quentin Perret, linux-arm-kernel, kvmarm, kvmarm, linux-kernel
hyp_get_page_state() is used with pKVM to retrieve metadata about a page
by parsing a hypervisor stage-1 PTE. However, it incorrectly uses a
helper which parses *stage-2* mappings. Ouch.
Luckily, pkvm_getstate() only looks at the software bits, which happen
to be in the same place for stage-1 and stage-2 PTEs, and this all ends
up working correctly by accident. But clearly, we should do better.
Fix hyp_get_page_state() to use the correct helper.
Fixes: e82edcc75c4e ("KVM: arm64: Implement do_share() helper for sharing memory")
Signed-off-by: Quentin Perret <qperret@google.com>
---
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 1e78acf9662e..07f9dc9848ef 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -516,7 +516,7 @@ static enum pkvm_page_state hyp_get_page_state(kvm_pte_t pte)
if (!kvm_pte_valid(pte))
return PKVM_NOPAGE;
- return pkvm_getstate(kvm_pgtable_stage2_pte_prot(pte));
+ return pkvm_getstate(kvm_pgtable_hyp_pte_prot(pte));
}
static int __hyp_check_page_state_range(u64 addr, u64 size,
--
2.38.0.135.g90850a2211-goog
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [PATCH] KVM: arm64: Use correct accessor to parse stage-1 PTEs
2022-10-25 14:51 [PATCH] KVM: arm64: Use correct accessor to parse stage-1 PTEs Quentin Perret
@ 2022-10-25 15:30 ` Marc Zyngier
0 siblings, 0 replies; 2+ messages in thread
From: Marc Zyngier @ 2022-10-25 15:30 UTC (permalink / raw)
To: Alexandru Elisei, Oliver Upton, Quentin Perret, Suzuki K Poulose,
Will Deacon, Catalin Marinas, James Morse
Cc: kvmarm, linux-kernel, kvmarm, linux-arm-kernel
On Tue, 25 Oct 2022 14:51:56 +0000, Quentin Perret wrote:
> hyp_get_page_state() is used with pKVM to retrieve metadata about a page
> by parsing a hypervisor stage-1 PTE. However, it incorrectly uses a
> helper which parses *stage-2* mappings. Ouch.
>
> Luckily, pkvm_getstate() only looks at the software bits, which happen
> to be in the same place for stage-1 and stage-2 PTEs, and this all ends
> up working correctly by accident. But clearly, we should do better.
>
> [...]
Applied to fixes, thanks!
[1/1] KVM: arm64: Use correct accessor to parse stage-1 PTEs
commit: 6853a71726b6f5930b4450889faf02e8f1cfe35c
Cheers,
M.
--
Without deviation from the norm, progress is not possible.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-10-25 14:51 [PATCH] KVM: arm64: Use correct accessor to parse stage-1 PTEs Quentin Perret
2022-10-25 15:30 ` Marc Zyngier
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