From: David Hoppenbrouwers <david@salt-inc.org> To: qemu-devel@nongnu.org Cc: Bin Meng <bin.meng@windriver.com>, Palmer Dabbelt <palmer@dabbelt.com>, David Hoppenbrouwers <david@salt-inc.org>, Alistair Francis <Alistair.Francis@wdc.com>, "open list:SiFive Machines" <qemu-riscv@nongnu.org> Subject: [PATCH] hw/intc/sifive_clint: Fix overflow in sifive_clint_write_timecmp() Date: Mon, 16 Aug 2021 19:30:35 +0200 [thread overview] Message-ID: <20210816173035.5165-1-david@salt-inc.org> (raw) `next` is an `uint64_t` value, but `timer_mod` takes an `int64_t`. This resulted in high values such as `UINT64_MAX` being converted to `-1`, which caused an immediate timer interrupt. By limiting `next` to `INT64_MAX` no overflow will happen while the timer will still be effectively set to "infinitely" far in the future. Resolves: https://gitlab.com/qemu-project/qemu/-/issues/493 Signed-off-by: David Hoppenbrouwers <david@salt-inc.org> --- hw/intc/sifive_clint.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/hw/intc/sifive_clint.c b/hw/intc/sifive_clint.c index 0f41e5ea1c..e65e71e5ec 100644 --- a/hw/intc/sifive_clint.c +++ b/hw/intc/sifive_clint.c @@ -61,6 +61,8 @@ static void sifive_clint_write_timecmp(RISCVCPU *cpu, uint64_t value, /* back to ns (note args switched in muldiv64) */ next = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + muldiv64(diff, NANOSECONDS_PER_SECOND, timebase_freq); + /* ensure next does not overflow, as timer_mod takes a signed value */ + next = MAX(next, INT64_MAX); timer_mod(cpu->env.timer, next); } -- 2.20.1
WARNING: multiple messages have this Message-ID (diff)
From: David Hoppenbrouwers <david@salt-inc.org> To: qemu-devel@nongnu.org Cc: David Hoppenbrouwers <david@salt-inc.org>, Alistair Francis <Alistair.Francis@wdc.com>, Bin Meng <bin.meng@windriver.com>, Palmer Dabbelt <palmer@dabbelt.com>, qemu-riscv@nongnu.org (open list:SiFive Machines) Subject: [PATCH] hw/intc/sifive_clint: Fix overflow in sifive_clint_write_timecmp() Date: Mon, 16 Aug 2021 19:30:35 +0200 [thread overview] Message-ID: <20210816173035.5165-1-david@salt-inc.org> (raw) `next` is an `uint64_t` value, but `timer_mod` takes an `int64_t`. This resulted in high values such as `UINT64_MAX` being converted to `-1`, which caused an immediate timer interrupt. By limiting `next` to `INT64_MAX` no overflow will happen while the timer will still be effectively set to "infinitely" far in the future. Resolves: https://gitlab.com/qemu-project/qemu/-/issues/493 Signed-off-by: David Hoppenbrouwers <david@salt-inc.org> --- hw/intc/sifive_clint.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/hw/intc/sifive_clint.c b/hw/intc/sifive_clint.c index 0f41e5ea1c..e65e71e5ec 100644 --- a/hw/intc/sifive_clint.c +++ b/hw/intc/sifive_clint.c @@ -61,6 +61,8 @@ static void sifive_clint_write_timecmp(RISCVCPU *cpu, uint64_t value, /* back to ns (note args switched in muldiv64) */ next = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + muldiv64(diff, NANOSECONDS_PER_SECOND, timebase_freq); + /* ensure next does not overflow, as timer_mod takes a signed value */ + next = MAX(next, INT64_MAX); timer_mod(cpu->env.timer, next); } -- 2.20.1
next reply other threads:[~2021-08-16 18:11 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-08-16 17:30 David Hoppenbrouwers [this message] 2021-08-16 17:30 ` [PATCH] hw/intc/sifive_clint: Fix overflow in sifive_clint_write_timecmp() David Hoppenbrouwers
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