Commit ce17c643 authored by Jes Sorensen's avatar Jes Sorensen Committed by Avi Kivity

KVM: ia64: SN2 adjust emulated ITC frequency to match RTC frequency

On SN2 do not pass down the real ITC frequency, but rather patch the
values to match the SN2 RTC frequency.
Signed-off-by: default avatarJes Sorensen <jes@sgi.com>
Acked-by: default avatarXiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent c6c9fcdf
...@@ -21,6 +21,9 @@ ...@@ -21,6 +21,9 @@
#include <linux/kvm_host.h> #include <linux/kvm_host.h>
#include <linux/smp.h> #include <linux/smp.h>
#include <asm/sn/addrs.h>
#include <asm/sn/clksupport.h>
#include <asm/sn/shub_mmr.h>
#include "vti.h" #include "vti.h"
#include "misc.h" #include "misc.h"
...@@ -188,12 +191,35 @@ static struct ia64_pal_retval pal_freq_base(struct kvm_vcpu *vcpu) ...@@ -188,12 +191,35 @@ static struct ia64_pal_retval pal_freq_base(struct kvm_vcpu *vcpu)
return result; return result;
} }
static struct ia64_pal_retval pal_freq_ratios(struct kvm_vcpu *vcpu) /*
* On the SGI SN2, the ITC isn't stable. Emulation backed by the SN2
* RTC is used instead. This function patches the ratios from SAL
* to match the RTC before providing them to the guest.
*/
static void sn2_patch_itc_freq_ratios(struct ia64_pal_retval *result)
{ {
struct pal_freq_ratio *ratio;
unsigned long sal_freq, sal_drift, factor;
result->status = ia64_sal_freq_base(SAL_FREQ_BASE_PLATFORM,
&sal_freq, &sal_drift);
ratio = (struct pal_freq_ratio *)&result->v2;
factor = ((sal_freq * 3) + (sn_rtc_cycles_per_second / 2)) /
sn_rtc_cycles_per_second;
ratio->num = 3;
ratio->den = factor;
}
static struct ia64_pal_retval pal_freq_ratios(struct kvm_vcpu *vcpu)
{
struct ia64_pal_retval result; struct ia64_pal_retval result;
PAL_CALL(result, PAL_FREQ_RATIOS, 0, 0, 0); PAL_CALL(result, PAL_FREQ_RATIOS, 0, 0, 0);
if (vcpu->kvm->arch.is_sn2)
sn2_patch_itc_freq_ratios(&result);
return result; return result;
} }
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment