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[Qemu-devel] [PULL 02/16] spapr/target-ppc/kvm: Only add hcall-instructi
From: |
David Gibson |
Subject: |
[Qemu-devel] [PULL 02/16] spapr/target-ppc/kvm: Only add hcall-instructions if KVM supports it |
Date: |
Thu, 24 Mar 2016 15:30:44 +1100 |
From: Alexey Kardashevskiy <address@hidden>
ePAPR defines "hcall-instructions" device-tree property which contains
code to call hypercalls in ePAPR paravirtualized guests. In general
pseries guests won't use this property, instead using the PAPR defined
hypercall interface.
However, this property has been re-used to implement a hack to allow
PR KVM to run (slightly modified) guests in some situations where it
otherwise wouldn't be able to (because the system's L0 hypervisor
doesn't forward the PAPR hypercalls to the PR KVM kernel).
Hence, this property is always present in the device tree for pseries
guests. All KVM guests use it at least to read features via the
KVM_HC_FEATURES hypercall.
The property is populated by the code returned from the KVM's
KVM_PPC_GET_PVINFO ioctl; if not implemented in the KVM, QEMU supplies
code which will fail all hypercall attempts. If QEMU does not create
the property, and the guest kernel is compiled with
CONFIG_EPAPR_PARAVIRT (which is normally the case), there is exactly
the same stub at @epapr_hypercall_start already.
Rather than maintaining this fairly useless stub implementation, it
makes more sense not to create the property in the device tree in the
first place if the host kernel does not implement it.
This changes kvmppc_get_hypercall() to return 1 if the host kernel
does not implement KVM_CAP_PPC_GET_PVINFO. The caller can use it to decide
on whether to create the property or not.
This changes the pseries machine to not create the property if KVM does
not implement KVM_PPC_GET_PVINFO. In practice this means that from now
on the property will not be created if either HV KVM or TCG is used.
Signed-off-by: Alexey Kardashevskiy <address@hidden>
[reworded commit message for clarity --dwg]
Signed-off-by: David Gibson <address@hidden>
---
hw/ppc/spapr.c | 9 +++++----
target-ppc/kvm.c | 2 +-
2 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index d0bb423..d43d6d9 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -497,10 +497,11 @@ static void *spapr_create_fdt_skel(hwaddr initrd_base,
* Older KVM versions with older guest kernels were broken with the
* magic page, don't allow the guest to map it.
*/
- kvmppc_get_hypercall(first_cpu->env_ptr, hypercall,
- sizeof(hypercall));
- _FDT((fdt_property(fdt, "hcall-instructions", hypercall,
- sizeof(hypercall))));
+ if (!kvmppc_get_hypercall(first_cpu->env_ptr, hypercall,
+ sizeof(hypercall))) {
+ _FDT((fdt_property(fdt, "hcall-instructions", hypercall,
+ sizeof(hypercall))));
+ }
}
_FDT((fdt_end_node(fdt)));
}
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index 2fc9931..20f113a 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -2007,7 +2007,7 @@ int kvmppc_get_hypercall(CPUPPCState *env, uint8_t *buf,
int buf_len)
hc[2] = cpu_to_be32(0x48000008);
hc[3] = cpu_to_be32(bswap32(0x3860ffff));
- return 0;
+ return 1;
}
static inline int kvmppc_enable_hcall(KVMState *s, target_ulong hcall)
--
2.5.5
- [Qemu-devel] [PULL 05/16] ppc: Add a bunch of hypervisor SPRs to Book3s, (continued)
- [Qemu-devel] [PULL 05/16] ppc: Add a bunch of hypervisor SPRs to Book3s, David Gibson, 2016/03/24
- [Qemu-devel] [PULL 01/16] ppc64: set MSR_SF bit, David Gibson, 2016/03/24
- [Qemu-devel] [PULL 04/16] ppc: Add macros to register hypervisor mode SPRs, David Gibson, 2016/03/24
- [Qemu-devel] [PULL 14/16] hw/net/spapr_llan: Fix receive buffer handling for better performance, David Gibson, 2016/03/24
- [Qemu-devel] [PULL 08/16] ppc: Initialize AMOR in PAPR mode, David Gibson, 2016/03/24
- [Qemu-devel] [PULL 11/16] ppc: Add dummy CIABR SPR, David Gibson, 2016/03/24
- [Qemu-devel] [PULL 15/16] hw/net/spapr_llan: Enable the RX buffer pools by default for new machines, David Gibson, 2016/03/24
- [Qemu-devel] [PULL 06/16] ppc: Create cpu_ppc_set_papr() helper, David Gibson, 2016/03/24
- [Qemu-devel] [PULL 07/16] ppc: Add dummy SPR_IC for POWER8, David Gibson, 2016/03/24
- [Qemu-devel] [PULL 12/16] ppc: A couple more dummy POWER8 Book4 regs, David Gibson, 2016/03/24
- [Qemu-devel] [PULL 02/16] spapr/target-ppc/kvm: Only add hcall-instructions if KVM supports it,
David Gibson <=
- [Qemu-devel] [PULL 03/16] ppc: Update SPR definitions, David Gibson, 2016/03/24
- [Qemu-devel] [PULL 13/16] hw/net/spapr_llan: Extract rx buffer code into separate functions, David Gibson, 2016/03/24
- [Qemu-devel] [PULL 09/16] ppc: Fix writing to AMR/UAMOR, David Gibson, 2016/03/24
- [Qemu-devel] [PULL 10/16] ppc: Add POWER8 IAMR register, David Gibson, 2016/03/24
- [Qemu-devel] [PULL 16/16] ppc: move POWER8 Book4 regs in their own routine, David Gibson, 2016/03/24
- Re: [Qemu-devel] [PULL 00/16] ppc-for-2.6 queue 20160324, Peter Maydell, 2016/03/24