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Re: [Qemu-ppc] [PATCH 1/2] target-ppc/kvm: Add a wrapper function to che
From: |
David Gibson |
Subject: |
Re: [Qemu-ppc] [PATCH 1/2] target-ppc/kvm: Add a wrapper function to check for KVM-PR |
Date: |
Fri, 30 Sep 2016 09:23:09 +1000 |
User-agent: |
Mutt/1.7.0 (2016-08-17) |
On Thu, Sep 29, 2016 at 12:48:06PM +0200, Thomas Huth wrote:
> It makes more sense if we have a proper function to check
> for KVM-PR than to check for the GET_PVINFO extension all
> over the place.
>
> Signed-off-by: Thomas Huth <address@hidden>
Applied to ppc-for-2.8. I expanded your comment to say this should
only be used for fallback tests, though.
> ---
> target-ppc/kvm.c | 23 +++++++++++++----------
> 1 file changed, 13 insertions(+), 10 deletions(-)
>
> diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
> index e9a9faf..dca50bc 100644
> --- a/target-ppc/kvm.c
> +++ b/target-ppc/kvm.c
> @@ -102,6 +102,13 @@ static void kvm_kick_cpu(void *opaque)
> qemu_cpu_kick(CPU(cpu));
> }
>
> +/* Check whether we are running with KVM-PR (instead of KVM-HV) */
> +static bool kvmppc_is_pr(KVMState *ks)
> +{
> + /* Assume KVM-PR if the GET_PVINFO capability is available */
> + return kvm_check_extension(ks, KVM_CAP_PPC_GET_PVINFO) != 0;
> +}
> +
> static int kvm_ppc_register_host_cpu_type(void);
>
> int kvm_arch_init(MachineState *ms, KVMState *s)
> @@ -223,10 +230,9 @@ static void kvm_get_fallback_smmu_info(PowerPCCPU *cpu,
> *
> * For that to work we make a few assumptions:
> *
> - * - If KVM_CAP_PPC_GET_PVINFO is supported we are running "PR"
> - * KVM which only supports 4K and 16M pages, but supports them
> - * regardless of the backing store characteritics. We also don't
> - * support 1T segments.
> + * - Check whether we are running "PR" KVM which only supports 4K
> + * and 16M pages, but supports them regardless of the backing
> + * store characteritics. We also don't support 1T segments.
> *
> * This is safe as if HV KVM ever supports that capability or PR
> * KVM grows supports for more page/segment sizes, those versions
> @@ -241,7 +247,7 @@ static void kvm_get_fallback_smmu_info(PowerPCCPU *cpu,
> * implements KVM_CAP_PPC_GET_SMMU_INFO and thus doesn't hit
> * this fallback.
> */
> - if (kvm_check_extension(cs->kvm_state, KVM_CAP_PPC_GET_PVINFO)) {
> + if (kvmppc_is_pr(cs->kvm_state)) {
> /* No flags */
> info->flags = 0;
> info->slb_size = 64;
> @@ -2270,11 +2276,8 @@ int kvmppc_reset_htab(int shift_hint)
>
> /* We have a kernel that predates the htab reset calls. For PR
> * KVM, we need to allocate the htab ourselves, for an HV KVM of
> - * this era, it has allocated a 16MB fixed size hash table
> - * already. Kernels of this era have the GET_PVINFO capability
> - * only on PR, so we use this hack to determine the right
> - * answer */
> - if (kvm_check_extension(kvm_state, KVM_CAP_PPC_GET_PVINFO)) {
> + * this era, it has allocated a 16MB fixed size hash table already. */
> + if (kvmppc_is_pr(kvm_state)) {
> /* PR - tell caller to allocate htab */
> return 0;
> } else {
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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