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authorDavid Gibson <david@gibson.dropbear.id.au>2015-05-07 15:33:59 +1000
committerAlexander Graf <agraf@suse.de>2015-06-03 23:56:55 +0200
commit026bfd89cb896c8a3460cc551cc4836219bd7ff9 (patch)
tree0184f5e47dd4b528355f5bdfb9d381b3a760556d /hw
parenta34944fe2e2457309bde74c1ffe3a1c60c6da018 (diff)
pseries: Enable in-kernel H_LOGICAL_CI_{LOAD, STORE} implementations
qemu currently implements the hypercalls H_LOGICAL_CI_LOAD and H_LOGICAL_CI_STORE as PAPR extensions. These are used by the SLOF firmware for IO, because performing cache inhibited MMIO accesses with the MMU off (real mode) is very awkward on POWER. This approach breaks when SLOF needs to access IO devices implemented within KVM instead of in qemu. The simplest example would be virtio-blk using an iothread, because the iothread / dataplane mechanism relies on an in-kernel implementation of the virtio queue notification MMIO. To fix this, an in-kernel implementation of these hypercalls has been made, (kernel commit 99342cf "kvmppc: Implement H_LOGICAL_CI_{LOAD,STORE} in KVM" however, the hypercalls still need to be enabled from qemu. This performs the necessary calls to do so. It would be nice to provide some warning if we encounter a problematic device with a kernel which doesn't support the new calls. Unfortunately, I can't see a way to detect this case which won't either warn in far too many cases that will probably work, or which is horribly invasive. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Reviewed-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Alexander Graf <agraf@suse.de>
Diffstat (limited to 'hw')
-rw-r--r--hw/ppc/spapr.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 2e9ac87630..f174e5a0f3 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1506,6 +1506,11 @@ static void ppc_spapr_init(MachineState *machine)
qemu_register_reset(spapr_cpu_reset, cpu);
}
+ if (kvm_enabled()) {
+ /* Enable H_LOGICAL_CI_* so SLOF can talk to in-kernel devices */
+ kvmppc_enable_logical_ci_hcalls();
+ }
+
/* allocate RAM */
spapr->ram_limit = ram_size;
memory_region_allocate_system_memory(ram, NULL, "ppc_spapr.ram",