[PATCH v2 06/39] xen/riscv: use UINT64_MAX to disable the VS-timer

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

vstimecmp is a 64-bit CSR independently of XLEN, which is why it is
written with csr_write64(). On RV32 that macro splits the value into
the vstimecmp/vstimecmph pair, so passing ULONG_MAX (0xffffffff there)
writes all ones to the low half and zero to the high half, leaving the
CSR at 0x00000000ffffffff rather than at its maximum. A VS-timer irq
would then become pending as soon as (time + htimedelta) reaches 2^32,
which is exactly what the code is trying to avoid.

Use UINT64_MAX, which matches the width of the CSR. On RV64 it is equal
to ULONG_MAX, so no functional change there.

Fixes: 25e032730690 ("xen/riscv: allow Xen to use SSTC while hiding it from 
guests")
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
Changes in v2:
 - New patch.
---
---
 xen/arch/riscv/time.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/arch/riscv/time.c b/xen/arch/riscv/time.c
index 602c029641b8..8c25198b4063 100644
--- a/xen/arch/riscv/time.c
+++ b/xen/arch/riscv/time.c
@@ -101,8 +101,8 @@ void __init preinit_xen_time(void)
          * A VS-timer interrupt becomes pending whenever the value of
          * (time + htimedelta) is greater than or equal to vstimecmp CSR.
          * Thereby to avoid spurious VS-timer irqs set vstimecmp CSR to
-         * ULONG_MAX.
+         * UINT64_MAX.
          */
-        csr_write64(CSR_VSTIMECMP, ULONG_MAX);
+        csr_write64(CSR_VSTIMECMP, UINT64_MAX);
     }
 }
-- 
2.55.0