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hv: add VHWP guest flag and its helper func

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Currently CPU frequency control is hidden to guests, and controlled
by hypervisor. While it is sufficient in most cases, some guest OS may
still need CPU performance info to make multi-core scheduling decisions.
This is seen on Linux kernel, which uses HWP highest performance level
as CPU core's priority in multi-core scheduling (CONFIG_SCHED_MC_PRIO).
Enabling this kernel feature could improve performance as single thread
workloads are scheduled on the highest performance cores. This is
significantly useful for guests with hybrid cores.

The concept is to expose performance interface to guest who exclusively
owns pCPU assigned to it. So that Linux guest can load intel_pstate
driver which will then provide the kernel with each core's schedule
priority.

Intel_pstate driver also relies on CONFIG_ACPI_CPPC_LIB to implement
this mechanic, this means we also need to provide ACPI _CPC in DM.

This patch sets up a guest flag GUEST_FLAG_VHWP to indicate whether
the guest can have VHWP feature.

Tracked-On: #8414
Signed-off-by: Wu Zhou <wu.zhou@intel.com>
Reviewed-by: Junjie Mao <junjie.mao@intel.com>
This commit is contained in:
Wu Zhou
2023-04-23 17:27:34 +08:00
committed by acrnsi-robot
parent e4e25f076c
commit 2edf141047
3 changed files with 12 additions and 1 deletions
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10
hypervisor/arch/x86/guest/vm.c
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@@ -213,6 +213,16 @@ bool is_static_configured_vm(const struct acrn_vm *vm)
return ((vm_config->guest_flags & GUEST_FLAG_STATIC_VM) != 0U);
}
/**
* @pre vm != NULL && vm_config != NULL && vm->vmid < CONFIG_MAX_VM_NUM
*/
bool is_vhwp_configured(const struct acrn_vm *vm)
{
struct acrn_vm_config *vm_config = get_vm_config(vm->vm_id);
return ((vm_config->guest_flags & GUEST_FLAG_VHWP) != 0U);
}
/**
* @brief VT-d PI posted mode can possibly be used for PTDEVs assigned
* to this VM if platform supports VT-d PI AND lapic passthru is not configured