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MIPS: KVM: Override guest kernel timer frequency directly

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The KVM_HOST_FREQ Kconfig symbol was used by KVM guest kernels to
override the timer frequency calculation to a value based on the host
frequency. Now that the KVM timer emulation is implemented independent
of the host timer frequency and defaults to 100MHz, adjust the working
of CONFIG_KVM_HOST_FREQ to match.

The Kconfig symbol now specifies the guest timer frequency directly, and
has been renamed accordingly to KVM_GUEST_TIMER_FREQ. It now defaults to
100MHz too and the help text is updated to make it clear that a zero
value will allow the normal timer frequency calculation to take place
(based on the emulated RTC).

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: Sanjay Lal <sanjayl@kymasys.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
James Hogan 2014-05-29 10:16:36 +01:00 committed by Paolo Bonzini
parent e30492bbe9
commit eda3d33c68
2 changed files with 8 additions and 18 deletions
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12
arch/mips/Kconfig
View file

@ -1756,14 +1756,14 @@ config KVM_GUEST
help
Select this option if building a guest kernel for KVM (Trap & Emulate) mode
config KVM_HOST_FREQ
int "KVM Host Processor Frequency (MHz)"
config KVM_GUEST_TIMER_FREQ
int "Count/Compare Timer Frequency (MHz)"
depends on KVM_GUEST
default 500
default 100
help
Select this option if building a guest kernel for KVM to skip
RTC emulation when determining guest CPU Frequency. Instead, the guest
processor frequency is automatically derived from the host frequency.
Set this to non-zero if building a guest kernel for KVM to skip RTC
emulation when determining guest CPU Frequency. Instead, the guest's
timer frequency is specified directly.
choice
prompt "Kernel page size"

14
arch/mips/mti-malta/malta-time.c
View file

@ -74,18 +74,8 @@ static void __init estimate_frequencies(void)
unsigned int giccount = 0, gicstart = 0;
#endif
#if defined (CONFIG_KVM_GUEST) && defined (CONFIG_KVM_HOST_FREQ)
unsigned int prid = read_c0_prid() & (PRID_COMP_MASK | PRID_IMP_MASK);
/*
* XXXKYMA: hardwire the CPU frequency to Host Freq/4
*/
count = (CONFIG_KVM_HOST_FREQ * 1000000) >> 3;
if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) &&
(prid != (PRID_COMP_MIPS | PRID_IMP_25KF)))
count *= 2;
mips_hpt_frequency = count;
#if defined(CONFIG_KVM_GUEST) && CONFIG_KVM_GUEST_TIMER_FREQ
mips_hpt_frequency = CONFIG_KVM_GUEST_TIMER_FREQ * 1000000;
return;
#endif