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Tsirkin" , wanghaibin.wang@huawei.com, qemu-devel@nongnu.org, Igor Mammedov , yuzenghui@huawei.com, Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2021/7/12 23:30, Daniel P. Berrangé wrote: > On Mon, Jul 12, 2021 at 05:00:48PM +0200, Andrew Jones wrote: >> On Fri, Jul 02, 2021 at 06:07:35PM +0800, Yanan Wang wrote: >>> We currently perform zero-check (default the value to 1 if zeroed) >>> for the computed values of cores/threads, to make sure they are at >>> least 1. For consistency, we probably should also default sockets >>> to 1 if the computed value is zero. Note that this won't affect >>> any existing working cmdlines but will improve the error reporting >>> of the invalid ones such as "-smp 8,maxcpus=9,cores=10,threads=1". >> How does this help error checking? If the user input values that compute a >> fractional (rounded down to zero with integer division) value, then we'll >> catch that with the sockets*cores*threads == maxcpus test now, but we may >> not catch that after this patch. > Since we're having alot of debates about what should be valid scenarios > vs invalid scenarios, I think this points towards introducing a tests > for the smp_parse function, that enumerates both the correct and > incorrect scenarios based on the current implementation. I think so! Actually I'm already working on a simple QEMU unit test (test-smp-parse.c) for smp parsing and plan to post it in v2. But it will directly test the finally improved generic parser. Thanks, Yanan . > This series should then update the test cases for scenarios that we > think are currently wrongly handled. > >> Thanks, >> drew >> >>> Signed-off-by: Yanan Wang >>> --- >>> hw/core/machine.c | 1 + >>> hw/i386/pc.c | 1 + >>> 2 files changed, 2 insertions(+) >>> >>> diff --git a/hw/core/machine.c b/hw/core/machine.c >>> index f17bbe3275..1e194677cd 100644 >>> --- a/hw/core/machine.c >>> +++ b/hw/core/machine.c >>> @@ -761,6 +761,7 @@ static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp) >>> } else { >>> maxcpus = maxcpus > 0 ? maxcpus : cpus; >>> sockets = maxcpus / (cores * threads); >>> + sockets = sockets > 0 ? sockets : 1; >>> } >>> } else if (cores == 0) { >>> threads = threads > 0 ? threads : 1; >>> diff --git a/hw/i386/pc.c b/hw/i386/pc.c >>> index a9b22fdc01..a44511c937 100644 >>> --- a/hw/i386/pc.c >>> +++ b/hw/i386/pc.c >>> @@ -729,6 +729,7 @@ static void pc_smp_parse(MachineState *ms, SMPConfiguration *config, Error **err >>> } else { >>> maxcpus = maxcpus > 0 ? maxcpus : cpus; >>> sockets = maxcpus / (dies * cores * threads); >>> + sockets = sockets > 0 ? sockets : 1; >>> } >>> } else if (cores == 0) { >>> threads = threads > 0 ? threads : 1; >>> -- >>> 2.19.1 >>> > Regards, > Daniel