6291e25165
- sync some bugfix patches from upstream - support vhostuser disk - libvirt: support dirtyrate (calc-dirty-rate, dirtyrate-param.mode) Signed-off-by: yezengruan <yezengruan@huawei.com>
96 lines
3.6 KiB
Diff
96 lines
3.6 KiB
Diff
From e24914dcbeb169f2608fd03cf6e701697844e065 Mon Sep 17 00:00:00 2001
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From: tangbinzy <tangbin_yewu@cmss.chinamobile.com>
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Date: Wed, 30 Nov 2022 09:38:41 +0000
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Subject: [PATCH 12/24] qemu: Do not require TSC frequency to strictly match
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host Some CPUs provide a way to read exact TSC frequency, while measuring it
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is required on other CPUs. However, measuring is never exact and the result
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may slightly differ across reboots. For this reason both Linux kernel and
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QEMU recently started allowing for guests TSC frequency to fall into +/- 250
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ppm tolerance interval around the host TSC frequency.
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Let's do the same to avoid unnecessary failures (esp. during migration)
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in case the host frequency does not exactly match the frequency
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configured in a domain XML.
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https://bugzilla.redhat.com/show_bug.cgi?id=1839095
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Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
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Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
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Signed-off-by: tangbin <tangbin_yewu@cmss.chinamobile.com>
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(cherry-pick from d8e5b4560006590668d4669f54a46b08ec14c1a2)
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---
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src/qemu/qemu_process.c | 35 ++++++++++++++++++++++++++---------
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1 file changed, 26 insertions(+), 9 deletions(-)
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diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
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index 360c4fcbb1..9cbf34a046 100644
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--- a/src/qemu/qemu_process.c
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+++ b/src/qemu/qemu_process.c
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@@ -5271,12 +5271,18 @@ qemuProcessStartValidateDisks(virDomainObjPtr vm,
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}
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+/* 250 parts per million (ppm) is a half of NTP threshold */
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+#define TSC_TOLERANCE 250
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+
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static int
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qemuProcessStartValidateTSC(virQEMUDriverPtr driver,
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virDomainObjPtr vm)
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{
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size_t i;
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unsigned long long freq = 0;
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+ unsigned long long tolerance;
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+ unsigned long long minFreq;
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+ unsigned long long maxFreq;
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virHostCPUTscInfoPtr tsc;
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g_autoptr(virCPUDef) cpu = NULL;
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@@ -5302,23 +5308,34 @@ qemuProcessStartValidateTSC(virQEMUDriverPtr driver,
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}
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tsc = cpu->tsc;
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- VIR_DEBUG("Host TSC frequency %llu Hz, scaling %s",
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- tsc->frequency, virTristateBoolTypeToString(tsc->scaling));
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+ tolerance = tsc->frequency * TSC_TOLERANCE / 1000000;
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+ minFreq = tsc->frequency - tolerance;
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+ maxFreq = tsc->frequency + tolerance;
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+
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+ VIR_DEBUG("Host TSC frequency %llu Hz, scaling %s, tolerance +/- %llu Hz",
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+ tsc->frequency, virTristateBoolTypeToString(tsc->scaling),
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+ tolerance);
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+
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+ if (freq > minFreq && freq < maxFreq) {
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+ VIR_DEBUG("Requested TSC frequency is within tolerance interval");
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+ return 0;
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+ }
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- if (freq == tsc->frequency || tsc->scaling == VIR_TRISTATE_BOOL_YES)
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+ if (tsc->scaling == VIR_TRISTATE_BOOL_YES)
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return 0;
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if (tsc->scaling == VIR_TRISTATE_BOOL_ABSENT) {
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- VIR_DEBUG("TSC frequencies do not match and scaling support is "
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- "unknown, QEMU will try and possibly fail later");
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+ VIR_DEBUG("Requested TSC frequency falls outside tolerance range and "
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+ "scaling support is unknown, QEMU will try and possibly "
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+ "fail later");
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return 0;
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}
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virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
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- _("Requested TSC frequency %llu Hz does not match "
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- "host (%llu Hz) and TSC scaling is not supported "
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- "by the host CPU"),
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- freq, tsc->frequency);
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+ _("Requested TSC frequency %llu Hz is outside tolerance "
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+ "range ([%llu, %llu] Hz) around host frequency %llu Hz "
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+ "and TSC scaling is not supported by the host CPU"),
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+ freq, minFreq, maxFreq, tsc->frequency);
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return -1;
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}
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--
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2.27.0
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