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KVM: PPC: Book3S HV: Implement virtual mode H_PAGE_INIT handler 

Implement a virtual mode handler for the H_CALL H_PAGE_INIT which can be
used to zero or copy a guest page. The page is defined to be 4k and must
be 4k aligned.

The in-kernel handler halves the time to handle this H_CALL compared to
handling it in userspace for a radix guest.

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This commit is contained in:
Suraj Jitindar Singh 2019-03-22 17:05:44 +11:00 committed by Paul Mackerras
parent 345077c8e1
commit 2d34d1c3bb
1 changed files with 80 additions and 0 deletions
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80
arch/powerpc/kvm/book3s_hv.c
View File

@ -801,6 +801,80 @@ static int kvmppc_h_set_mode(struct kvm_vcpu *vcpu, unsigned long mflags,
}
}
/* Copy guest memory in place - must reside within a single memslot */
static int kvmppc_copy_guest(struct kvm *kvm, gpa_t to, gpa_t from,
unsigned long len)
{
struct kvm_memory_slot *to_memslot = NULL;
struct kvm_memory_slot *from_memslot = NULL;
unsigned long to_addr, from_addr;
int r;
/* Get HPA for from address */
from_memslot = gfn_to_memslot(kvm, from >> PAGE_SHIFT);
if (!from_memslot)
return -EFAULT;
if ((from + len) >= ((from_memslot->base_gfn + from_memslot->npages)
<< PAGE_SHIFT))
return -EINVAL;
from_addr = gfn_to_hva_memslot(from_memslot, from >> PAGE_SHIFT);
if (kvm_is_error_hva(from_addr))
return -EFAULT;
from_addr |= (from & (PAGE_SIZE - 1));
/* Get HPA for to address */
to_memslot = gfn_to_memslot(kvm, to >> PAGE_SHIFT);
if (!to_memslot)
return -EFAULT;
if ((to + len) >= ((to_memslot->base_gfn + to_memslot->npages)
<< PAGE_SHIFT))
return -EINVAL;
to_addr = gfn_to_hva_memslot(to_memslot, to >> PAGE_SHIFT);
if (kvm_is_error_hva(to_addr))
return -EFAULT;
to_addr |= (to & (PAGE_SIZE - 1));
/* Perform copy */
r = raw_copy_in_user((void __user *)to_addr, (void __user *)from_addr,
len);
if (r)
return -EFAULT;
mark_page_dirty(kvm, to >> PAGE_SHIFT);
return 0;
}
static long kvmppc_h_page_init(struct kvm_vcpu *vcpu, unsigned long flags,
unsigned long dest, unsigned long src)
{
u64 pg_sz = SZ_4K; /* 4K page size */
u64 pg_mask = SZ_4K - 1;
int ret;
/* Check for invalid flags (H_PAGE_SET_LOANED covers all CMO flags) */
if (flags & ~(H_ICACHE_INVALIDATE | H_ICACHE_SYNCHRONIZE |
H_ZERO_PAGE | H_COPY_PAGE | H_PAGE_SET_LOANED))
return H_PARAMETER;
/* dest (and src if copy_page flag set) must be page aligned */
if ((dest & pg_mask) || ((flags & H_COPY_PAGE) && (src & pg_mask)))
return H_PARAMETER;
/* zero and/or copy the page as determined by the flags */
if (flags & H_COPY_PAGE) {
ret = kvmppc_copy_guest(vcpu->kvm, dest, src, pg_sz);
if (ret < 0)
return H_PARAMETER;
} else if (flags & H_ZERO_PAGE) {
ret = kvm_clear_guest(vcpu->kvm, dest, pg_sz);
if (ret < 0)
return H_PARAMETER;
}
/* We can ignore the remaining flags */
return H_SUCCESS;
}
static int kvm_arch_vcpu_yield_to(struct kvm_vcpu *target)
{
struct kvmppc_vcore *vcore = target->arch.vcore;
@ -1003,6 +1077,11 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
if (nesting_enabled(vcpu->kvm))
ret = kvmhv_copy_tofrom_guest_nested(vcpu);
break;
case H_PAGE_INIT:
ret = kvmppc_h_page_init(vcpu, kvmppc_get_gpr(vcpu, 4),
kvmppc_get_gpr(vcpu, 5),
kvmppc_get_gpr(vcpu, 6));
break;
default:
return RESUME_HOST;
}
@ -1047,6 +1126,7 @@ static int kvmppc_hcall_impl_hv(unsigned long cmd)
case H_IPOLL:
case H_XIRR_X:
#endif
case H_PAGE_INIT:
return 1;
}