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authorPaul Mackerras <paulus@samba.org>2011-06-29 00:25:44 +0000
committerAvi Kivity <avi@redhat.com>2011-07-12 13:16:57 +0300
commitaa04b4cc5be64b4fb9ef4e0fdf2418e2f4737fb2 (patch)
tree97a3ff14e43424e28a27e0f3be088649818c1b76 /include/linux/kvm.h
parent371fefd6f2dc46668e00871930dde613b88d4bde (diff)
KVM: PPC: Allocate RMAs (Real Mode Areas) at boot for use by guests
This adds infrastructure which will be needed to allow book3s_hv KVM to run on older POWER processors, including PPC970, which don't support the Virtual Real Mode Area (VRMA) facility, but only the Real Mode Offset (RMO) facility. These processors require a physically contiguous, aligned area of memory for each guest. When the guest does an access in real mode (MMU off), the address is compared against a limit value, and if it is lower, the address is ORed with an offset value (from the Real Mode Offset Register (RMOR)) and the result becomes the real address for the access. The size of the RMA has to be one of a set of supported values, which usually includes 64MB, 128MB, 256MB and some larger powers of 2. Since we are unlikely to be able to allocate 64MB or more of physically contiguous memory after the kernel has been running for a while, we allocate a pool of RMAs at boot time using the bootmem allocator. The size and number of the RMAs can be set using the kvm_rma_size=xx and kvm_rma_count=xx kernel command line options. KVM exports a new capability, KVM_CAP_PPC_RMA, to signal the availability of the pool of preallocated RMAs. The capability value is 1 if the processor can use an RMA but doesn't require one (because it supports the VRMA facility), or 2 if the processor requires an RMA for each guest. This adds a new ioctl, KVM_ALLOCATE_RMA, which allocates an RMA from the pool and returns a file descriptor which can be used to map the RMA. It also returns the size of the RMA in the argument structure. Having an RMA means we will get multiple KMV_SET_USER_MEMORY_REGION ioctl calls from userspace. To cope with this, we now preallocate the kvm->arch.ram_pginfo array when the VM is created with a size sufficient for up to 64GB of guest memory. Subsequently we will get rid of this array and use memory associated with each memslot instead. This moves most of the code that translates the user addresses into host pfns (page frame numbers) out of kvmppc_prepare_vrma up one level to kvmppc_core_prepare_memory_region. Also, instead of having to look up the VMA for each page in order to check the page size, we now check that the pages we get are compound pages of 16MB. However, if we are adding memory that is mapped to an RMA, we don't bother with calling get_user_pages_fast and instead just offset from the base pfn for the RMA. Typically the RMA gets added after vcpus are created, which makes it inconvenient to have the LPCR (logical partition control register) value in the vcpu->arch struct, since the LPCR controls whether the processor uses RMA or VRMA for the guest. This moves the LPCR value into the kvm->arch struct and arranges for the MER (mediated external request) bit, which is the only bit that varies between vcpus, to be set in assembly code when going into the guest if there is a pending external interrupt request. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
Diffstat (limited to 'include/linux/kvm.h')
-rw-r--r--include/linux/kvm.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index e2a378d9716..2c366b52f50 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -552,6 +552,7 @@ struct kvm_ppc_pvinfo {
#define KVM_CAP_PPC_BOOKE_SREGS 62
#define KVM_CAP_SPAPR_TCE 63
#define KVM_CAP_PPC_SMT 64
+#define KVM_CAP_PPC_RMA 65
#ifdef KVM_CAP_IRQ_ROUTING
@@ -755,6 +756,8 @@ struct kvm_clock_data {
#define KVM_GET_XCRS _IOR(KVMIO, 0xa6, struct kvm_xcrs)
#define KVM_SET_XCRS _IOW(KVMIO, 0xa7, struct kvm_xcrs)
#define KVM_CREATE_SPAPR_TCE _IOW(KVMIO, 0xa8, struct kvm_create_spapr_tce)
+/* Available with KVM_CAP_RMA */
+#define KVM_ALLOCATE_RMA _IOR(KVMIO, 0xa9, struct kvm_allocate_rma)
#define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0)