[PATCH 1/2] drivers/virt: pkvm: Don't fail ioremap() call if MMIO_GUARD fails

[Will Deacon]

Calling the MMIO_GUARD hypercall from guests which have not been
enrolled (e.g. because they are running without pvmfw) results in
-EINVAL being returned. In this case, MMIO_GUARD is not active
and so we can simply proceed with the normal ioremap() routine.

Don't fail ioremap() if MMIO_GUARD fails; instead WARN_ON_ONCE()
to highlight that the pvm environment is slightly wonky.

Fixes: 0f1269495800 ("drivers/virt: pkvm: Intercept ioremap using pKVM MMIO_GUARD hypercal")
Signed-off-by: Will Deacon <will at kernel.org>
---
 drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c b/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c
index 56a3859dda8a..4230b817a80b 100644
--- a/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c
+++ b/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c
@@ -87,12 +87,8 @@ static int mmio_guard_ioremap_hook(phys_addr_t phys, size_t size,
 
 	while (phys < end) {
 		const int func_id = ARM_SMCCC_VENDOR_HYP_KVM_MMIO_GUARD_FUNC_ID;
-		int err;
-
-		err = arm_smccc_do_one_page(func_id, phys);
-		if (err)
-			return err;
 
+		WARN_ON_ONCE(arm_smccc_do_one_page(func_id, phys));
 		phys += PAGE_SIZE;
 	}
 
-- 
2.47.0.338.g60cca15819-goog