[PATCH 2/3] drivers/virt: pkvm: Fix end calculation in mmio_guard_ioremap_hook()

[Mostafa Saleh]

Sashiko (locally) reports a logical issues in mmio_guard_ioremap_hook()

mmio_guard_ioremap_hook() attempts to handle unaligned addresses and
sizes. However, aligning the start address before adding the size, might
shift the end to the page before.

Fixes: 0f1269495800 ("drivers/virt: pkvm: Intercept ioremap using pKVM MMIO_GUARD hypercall")
Signed-off-by: Mostafa Saleh <smostafa at google.com>
---
 drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c b/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c
index 4230b817a80b..d66291def0f4 100644
--- a/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c
+++ b/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c
@@ -82,8 +82,8 @@ static int mmio_guard_ioremap_hook(phys_addr_t phys, size_t size,
 	if (protval != PROT_DEVICE_nGnRE && protval != PROT_DEVICE_nGnRnE)
 		return 0;
 
+	end = PAGE_ALIGN(phys + size);
 	phys = PAGE_ALIGN_DOWN(phys);
-	end = phys + PAGE_ALIGN(size);
 
 	while (phys < end) {
 		const int func_id = ARM_SMCCC_VENDOR_HYP_KVM_MMIO_GUARD_FUNC_ID;
-- 
2.54.0.1032.g2f8565e1d1-goog