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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?SUJrVnhVbHJRR1UwTTRRd3I5N1orWHpmWmVuYUpMT0h4NkdmWEFQSDJkSU8v?= =?utf-8?B?bkMvVW9XVFppbTk4V3hVa0U5RHlTT2tSUlpjT001RHZEQ2o4Sk1XVVphYjZ1?= =?utf-8?B?MlRVZWlSUkN5US9QNWtJRmRZUkkwdXZQSjNidUdLWmkwWm1aMStEVm9jaTJI?= =?utf-8?B?OE9adDgzZUk0bGhXbXNCeFkzSkJ0ay82OGZaWU9xdnV5RlpqVWRlZlkzenZr?= =?utf-8?B?a2Q3Q2hVS0Z2QVRPNUpNZzQ5SE0wN0htL2hrNDV4YTB2MFJQQkphSGhwaEps?= =?utf-8?B?MUpvRTYwSVpSa0tzQy9Ga2RXTW9tZk9CUjZwWnJCUHhlVm9ZYU96N29aUEJt?= =?utf-8?B?Vk51M2V5UGFSOW5xWjFmay9RUDY2U0RrRlNCS012ZlpXNTA1RWFwZHJ6eFI0?= =?utf-8?B?d1RjZHRyQjhXYmIzWVYwdkxUSlBzWHk4TjNDck90dGxDWDE5dTY5T1N4QXJT?= =?utf-8?B?cHdLdGQra09lME05RjVUaFFGZzRtWENNN2tLb2dlbHBNS1pIaTM2c0paMDJD?= =?utf-8?B?cHVxSVpVNWlGMHI0dUo4enkvK1VWVTVRNXBaSVFzKytFazczcFpEN2tGbFBw?= =?utf-8?B?VnhHaFFWV05HMUREdjZUbDJwcEluOGZNcGFpbTNaSWkraHhTQ20yOG5FUTR5?= =?utf-8?B?RjNKdndpN250bC9SUVNkVWovUDBOOXZ3T25yTzNYN0NZRWpYdFdnZGZmTUZR?= =?utf-8?B?czkydGFNRjhGNkZCV2lxZDN2aHRydEx4ODcrSmR2M0k3aGd0VjV1R0lESGpN?= =?utf-8?B?TTl1ZHBVczNzSU9xZ1I4K2MrK251MGJNL3c3eVlpdEg4dHZLai9jS2ppZEJK?= =?utf-8?B?bENub29acU1ra3h6a3hBK291Tk1PL2hKQ2k2UkJtWmVjNHRBS2t2MGZSa1dk?= =?utf-8?B?bkxjZnJ5RUJLTTBkS0ptK294d0ZITldqd3FJcW5oV21NbkRiZHdhR3ZITzVo?= =?utf-8?B?QkJsVi9lczU0L09yRnVqR1NqQVNZQTBiVW54RzFXa05yOE52MzFxQUFIaitV?= =?utf-8?B?OVRJVEtvWld5ZUFyWlJzYXNGbUIrU0Y0TjN2QWhwVUxSUnBUN0c2R3NKNmo5?= =?utf-8?B?R1QxWlFadkk3TDEyVlRFRFRYQ3NURGQxUWgwMlVmc3k5bncwdHVXZTU4U0oz?= =?utf-8?B?Q3A3SkFXWkF3NEQvK0Z5eDczRTVIMjNDaExvVjNNMjRJZldLckxEYTVXRUhF?= =?utf-8?B?dzRoZGN2RWdvVnFuRW02c3RpTnVXU0ZDUExLd25GZ3ZsYzhFb1crckdNSE9B?= =?utf-8?B?cndYanZFdm4wdk1CWlBlT3htZ0pIa09VVmZCNi9YRlQ2K3M1U2NKazlreXFu?= =?utf-8?B?QVdvY3d3KzhTUDliTzF1UUNqenlKUXQxNlRGeUY0T051NWViUVorQ0FXUVB0?= =?utf-8?B?NFhqdXdERGxzc3dPY2xuWjYxcXpKZzBuSlRHbWlzdHc2SS9wSUt5SEpoN0VC?= =?utf-8?B?dTZHWEZOV3NTdXNjcmRnSGszZmpzNjEwR2w5UEIzUnkvN1ByRFNGS1RTTHBS?= =?utf-8?B?Y2s1V01PejRKOElYbGhweU5GVzJ4ak9sNjFSRXVyVE0xVExnL3lhSGhBVkxh?= =?utf-8?B?bHBOVUcrREQ1Rjc3MGFUczFBSGJFMnpxUlYyODluZFRsUmhNSlMwYmx4dGRV?= =?utf-8?B?alpmaWRESWM0TlJBd3JXMDVMZ21tR0U1Wmh4TVZSbzJoKzlCa2NwWStoNXox?= =?utf-8?B?bFdVSHhLTVM4SzVtVlhtTzFkMXgyZzZVRGh5N1pCM2RuenBCck1vUGgzVmsv?= =?utf-8?Q?du9Krv2nsF2MZAZKeP2uwJ4nUyr7dH/iMihA45D?= X-MS-Exchange-CrossTenant-Network-Message-Id: 9271573d-932d-4ee8-76ca-08d992f3d704 X-MS-Exchange-CrossTenant-AuthSource: DS7PR03MB5608.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Oct 2021 11:30:23.2942 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 335836de-42ef-43a2-b145-348c2ee9ca5b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: i76Dh1qrzwiKaBXMkcJ/Y47Cw/IgUNnsz+5ZbgRNhzajb7txnjgg7QRl22y0Qk7sfdUYyG4d2A8IMq5ErieFjg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR03MB2491 X-OriginatorOrg: citrix.com On Tue, Oct 19, 2021 at 09:07:39AM +0200, Jan Beulich wrote: > From: Thomas Gleixner > > On recent Intel systems the HPET stops working when the system reaches PC10 > idle state. > > The approach of adding PCI ids to the early quirks to disable HPET on > these systems is a whack a mole game which makes no sense. > > Check for PC10 instead and force disable HPET if supported. The check is > overbroad as it does not take ACPI, mwait-idle enablement and command > line parameters into account. That's fine as long as there is at least > PMTIMER available to calibrate the TSC frequency. The decision can be > overruled by adding "clocksource=hpet" on the Xen command line. > > Remove the related PCI quirks for affected Coffee Lake systems as they > are not longer required. That should also cover all other systems, i.e. > Ice Lake, Tiger Lake, and newer generations, which are most likely > affected by this as well. > > Fixes: Yet another hardware trainwreck > Reported-by: Jakub Kicinski > Signed-off-by: Thomas Gleixner > [Linux commit: 6e3cd95234dc1eda488f4f487c281bac8fef4d9b] > > I have to admit that the purpose of checking CPUID5_ECX_INTERRUPT_BREAK > is unclear to me, but I didn't want to diverge in technical aspects from > the Linux commit. > > In mwait_pc10_supported(), besides some cosmetic adjustments, avoid UB > from shifting left a signed 4-bit constant by 28 bits. > > Signed-off-by: Jan Beulich Acked-by: Roger Pau Monné Just one comment below. > --- > v2: Fully different replacement of "x86: avoid HPET use also on certain > Coffee Lake H". > > --- a/xen/arch/x86/time.c > +++ b/xen/arch/x86/time.c > @@ -34,6 +34,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -395,14 +396,43 @@ static int64_t __init init_hpet(struct p > } > > /* > - * Some Coffee Lake platforms have a skewed HPET timer once the SoCs > - * entered PC10. > + * Some Coffee Lake and later platforms have a skewed HPET timer once > + * they entered PC10. > + * > + * Check whether the system supports PC10. If so force disable HPET as > + * that stops counting in PC10. This check is overbroad as it does not > + * take any of the following into account: > + * > + * - ACPI tables > + * - Enablement of mwait-idle > + * - Command line arguments which limit mwait-idle C-state support > + * > + * That's perfectly fine. HPET is a piece of hardware designed by > + * committee and the only reasons why it is still in use on modern > + * systems is the fact that it is impossible to reliably query TSC and > + * CPU frequency via CPUID or firmware. > + * > + * If HPET is functional it is useful for calibrating TSC, but this can > + * be done via PMTIMER as well which seems to be the last remaining > + * timer on X86/INTEL platforms that has not been completely wreckaged > + * by feature creep. > + * > + * In theory HPET support should be removed altogether, but there are > + * older systems out there which depend on it because TSC and APIC timer > + * are dysfunctional in deeper C-states. > */ > - if ( pci_conf_read16(PCI_SBDF(0, 0, 0, 0), > - PCI_VENDOR_ID) == PCI_VENDOR_ID_INTEL && > - pci_conf_read16(PCI_SBDF(0, 0, 0, 0), > - PCI_DEVICE_ID) == 0x3ec4 ) > - hpet_address = 0; > + if ( mwait_pc10_supported() ) > + { > + uint64_t pcfg; > + > + rdmsrl(MSR_PKG_CST_CONFIG_CONTROL, pcfg); > + if ( (pcfg & 0xf) < 8 ) > + /* nothing */; > + else if ( !strcmp(opt_clocksource, pts->id) ) > + printk("HPET use requested via command line, but dysfunctional in PC10\n"); > + else > + hpet_address = 0; Should we print a message that HPET is being disabled? Thanks, Roger.