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linux/arch/powerpc/kvm/book3s_64_mmu_hv.c

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KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 00:21:34 +00:00
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* Copyright 2010 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
*/
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <linux/highmem.h>
#include <linux/gfp.h>
#include <linux/slab.h>
#include <linux/hugetlb.h>
#include <asm/tlbflush.h>
#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>
#include <asm/mmu-hash64.h>
#include <asm/hvcall.h>
#include <asm/synch.h>
#include <asm/ppc-opcode.h>
#include <asm/cputable.h>
/* For now use fixed-size 16MB page table */
#define HPT_ORDER 24
#define HPT_NPTEG (1ul << (HPT_ORDER - 7)) /* 128B per pteg */
#define HPT_HASH_MASK (HPT_NPTEG - 1)
/* Pages in the VRMA are 16MB pages */
#define VRMA_PAGE_ORDER 24
#define VRMA_VSID 0x1ffffffUL /* 1TB VSID reserved for VRMA */
#define NR_LPIDS (LPID_RSVD + 1)
unsigned long lpid_inuse[BITS_TO_LONGS(NR_LPIDS)];
long kvmppc_alloc_hpt(struct kvm *kvm)
{
unsigned long hpt;
unsigned long lpid;
hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_REPEAT|__GFP_NOWARN,
HPT_ORDER - PAGE_SHIFT);
if (!hpt) {
pr_err("kvm_alloc_hpt: Couldn't alloc HPT\n");
return -ENOMEM;
}
kvm->arch.hpt_virt = hpt;
do {
lpid = find_first_zero_bit(lpid_inuse, NR_LPIDS);
if (lpid >= NR_LPIDS) {
pr_err("kvm_alloc_hpt: No LPIDs free\n");
free_pages(hpt, HPT_ORDER - PAGE_SHIFT);
return -ENOMEM;
}
} while (test_and_set_bit(lpid, lpid_inuse));
kvm->arch.sdr1 = __pa(hpt) | (HPT_ORDER - 18);
kvm->arch.lpid = lpid;
kvm->arch.host_sdr1 = mfspr(SPRN_SDR1);
kvm->arch.host_lpid = mfspr(SPRN_LPID);
kvm->arch.host_lpcr = mfspr(SPRN_LPCR);
pr_info("KVM guest htab at %lx, LPID %lx\n", hpt, lpid);
return 0;
}
void kvmppc_free_hpt(struct kvm *kvm)
{
clear_bit(kvm->arch.lpid, lpid_inuse);
free_pages(kvm->arch.hpt_virt, HPT_ORDER - PAGE_SHIFT);
}
void kvmppc_map_vrma(struct kvm *kvm, struct kvm_userspace_memory_region *mem)
{
unsigned long i;
unsigned long npages = kvm->arch.ram_npages;
unsigned long pfn;
unsigned long *hpte;
unsigned long hash;
struct kvmppc_pginfo *pginfo = kvm->arch.ram_pginfo;
if (!pginfo)
return;
/* VRMA can't be > 1TB */
if (npages > 1ul << (40 - kvm->arch.ram_porder))
npages = 1ul << (40 - kvm->arch.ram_porder);
/* Can't use more than 1 HPTE per HPTEG */
if (npages > HPT_NPTEG)
npages = HPT_NPTEG;
for (i = 0; i < npages; ++i) {
pfn = pginfo[i].pfn;
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>
2011-06-29 00:25:44 +00:00
if (!pfn)
break;
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 00:21:34 +00:00
/* can't use hpt_hash since va > 64 bits */
hash = (i ^ (VRMA_VSID ^ (VRMA_VSID << 25))) & HPT_HASH_MASK;
/*
* We assume that the hash table is empty and no
* vcpus are using it at this stage. Since we create
* at most one HPTE per HPTEG, we just assume entry 7
* is available and use it.
*/
hpte = (unsigned long *) (kvm->arch.hpt_virt + (hash << 7));
hpte += 7 * 2;
/* HPTE low word - RPN, protection, etc. */
hpte[1] = (pfn << PAGE_SHIFT) | HPTE_R_R | HPTE_R_C |
HPTE_R_M | PP_RWXX;
wmb();
hpte[0] = HPTE_V_1TB_SEG | (VRMA_VSID << (40 - 16)) |
(i << (VRMA_PAGE_ORDER - 16)) | HPTE_V_BOLTED |
HPTE_V_LARGE | HPTE_V_VALID;
}
}
int kvmppc_mmu_hv_init(void)
{
powerpc, KVM: Split HVMODE_206 cpu feature bit into separate HV and architecture bits This replaces the single CPU_FTR_HVMODE_206 bit with two bits, one to indicate that we have a usable hypervisor mode, and another to indicate that the processor conforms to PowerISA version 2.06. We also add another bit to indicate that the processor conforms to ISA version 2.01 and set that for PPC970 and derivatives. Some PPC970 chips (specifically those in Apple machines) have a hypervisor mode in that MSR[HV] is always 1, but the hypervisor mode is not useful in the sense that there is no way to run any code in supervisor mode (HV=0 PR=0). On these processors, the LPES0 and LPES1 bits in HID4 are always 0, and we use that as a way of detecting that hypervisor mode is not useful. Where we have a feature section in assembly code around code that only applies on POWER7 in hypervisor mode, we use a construct like END_FTR_SECTION_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_206) The definition of END_FTR_SECTION_IFSET is such that the code will be enabled (not overwritten with nops) only if all bits in the provided mask are set. Note that the CPU feature check in __tlbie() only needs to check the ARCH_206 bit, not the HVMODE bit, because __tlbie() can only get called if we are running bare-metal, i.e. in hypervisor mode. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 00:26:11 +00:00
if (!cpu_has_feature(CPU_FTR_HVMODE) ||
!cpu_has_feature(CPU_FTR_ARCH_206))
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 00:21:34 +00:00
return -EINVAL;
memset(lpid_inuse, 0, sizeof(lpid_inuse));
set_bit(mfspr(SPRN_LPID), lpid_inuse);
set_bit(LPID_RSVD, lpid_inuse);
return 0;
}
void kvmppc_mmu_destroy(struct kvm_vcpu *vcpu)
{
}
static void kvmppc_mmu_book3s_64_hv_reset_msr(struct kvm_vcpu *vcpu)
{
kvmppc_set_msr(vcpu, MSR_SF | MSR_ME);
}
static int kvmppc_mmu_book3s_64_hv_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
struct kvmppc_pte *gpte, bool data)
{
return -ENOENT;
}
void kvmppc_mmu_book3s_hv_init(struct kvm_vcpu *vcpu)
{
struct kvmppc_mmu *mmu = &vcpu->arch.mmu;
vcpu->arch.slb_nr = 32; /* Assume POWER7 for now */
mmu->xlate = kvmppc_mmu_book3s_64_hv_xlate;
mmu->reset_msr = kvmppc_mmu_book3s_64_hv_reset_msr;
vcpu->arch.hflags |= BOOK3S_HFLAG_SLB;
}
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