The branch main has been updated by royger:
URL:
https://cgit.FreeBSD.org/src/commit/?id=1ca34862dc45e0074b5aa31d9e491a2684ac6640
commit 1ca34862dc45e0074b5aa31d9e491a2684ac6640
Author: Roger Pau Monné <roy...@freebsd.org>
AuthorDate: 2022-03-16 08:56:40 +0000
Commit: Roger Pau Monné <roy...@freebsd.org>
CommitDate: 2022-03-18 09:21:04 +0000
x86/tsc: fetch frequency from CPUID when running on Xen
Introduce a helper to fetch the TSC frequency from CPUID when running
under Xen.
Since the TSC can also be initialized early when running as a Xen
guest pull out the call to tsc_init() from the
early_clock_source_init() handlers and place it in clock_init(), as
otherwise all handlers would call tsc_init() anyway.
Reviewed by: markj
Sponsored by: Citrix Systems R&D
Differential revision: https://reviews.freebsd.org/D34581
---
sys/amd64/amd64/machdep.c | 1 -
sys/i386/i386/machdep.c | 1 -
sys/x86/isa/clock.c | 1 +
sys/x86/x86/tsc.c | 21 +++++++++++++++++++++
4 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index b7810440a551..55a278de6020 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -1167,7 +1167,6 @@ static void
native_clock_source_init(void)
{
i8254_init();
- tsc_init();
}
static void
diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index 6913c0691fd4..9fee973d9e82 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -208,7 +208,6 @@ static void
i386_clock_source_init(void)
{
i8254_init();
- tsc_init();
}
static void
diff --git a/sys/x86/isa/clock.c b/sys/x86/isa/clock.c
index f21f847709cd..730aee5e9a2a 100644
--- a/sys/x86/isa/clock.c
+++ b/sys/x86/isa/clock.c
@@ -129,6 +129,7 @@ clock_init(void)
mtx_init(&clock_lock, "clk", NULL, MTX_SPIN | MTX_NOPROFILE);
/* Init the clock in order to use DELAY */
init_ops.early_clock_source_init();
+ tsc_init();
}
static int
diff --git a/sys/x86/x86/tsc.c b/sys/x86/x86/tsc.c
index 0fdd70a690a3..96f209e4c08d 100644
--- a/sys/x86/x86/tsc.c
+++ b/sys/x86/x86/tsc.c
@@ -147,6 +147,21 @@ tsc_freq_vmware(void)
tsc_early_calib_exact = 1;
}
+static void
+tsc_freq_xen(void)
+{
+ u_int regs[4];
+
+ /*
+ * Must run *after* generic tsc_freq_cpuid_vm, so that when Xen is
+ * emulating Viridian support the Viridian leaf is used instead.
+ */
+ KASSERT(hv_high >= 0x40000003, ("Invalid max hypervisor leaf on Xen"));
+ cpuid_count(0x40000003, 0, regs);
+ tsc_freq = (uint64_t)(regs[2]) * 1000;
+ tsc_early_calib_exact = 1;
+}
+
/*
* Calculate TSC frequency using information from the CPUID leaf 0x15 'Time
* Stamp Counter and Nominal Core Crystal Clock'. If leaf 0x15 is not
@@ -358,6 +373,12 @@ probe_tsc_freq_early(void)
printf(
"Early TSC frequency %juHz derived from VMWare hypercall\n",
(uintmax_t)tsc_freq);
+ } else if (vm_guest == VM_GUEST_XEN) {
+ tsc_freq_xen();
+ if (bootverbose)
+ printf(
+ "Early TSC frequency %juHz derived from Xen CPUID\n",
+ (uintmax_t)tsc_freq);
} else if (tsc_freq_cpuid(&tsc_freq)) {
/*
* If possible, use the value obtained from CPUID as the initial
