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

Implement a real 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 real mode handler halves the time to handle this H_CALL
compared to handling it in userspace for a hash 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 17:05:45 +11:00 committed by Paul Mackerras
parent 2d34d1c3bb
commit eadfb1c5f8
3 changed files with 147 additions and 1 deletions

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@ -665,6 +665,8 @@ long kvmppc_h_clear_ref(struct kvm_vcpu *vcpu, unsigned long flags,
unsigned long pte_index);
long kvmppc_h_clear_mod(struct kvm_vcpu *vcpu, unsigned long flags,
unsigned long pte_index);
long kvmppc_rm_h_page_init(struct kvm_vcpu *vcpu, unsigned long flags,
unsigned long dest, unsigned long src);
long kvmppc_hpte_hv_fault(struct kvm_vcpu *vcpu, unsigned long addr,
unsigned long slb_v, unsigned int status, bool data);
unsigned long kvmppc_rm_h_xirr(struct kvm_vcpu *vcpu);

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@ -13,6 +13,7 @@
#include <linux/hugetlb.h>
#include <linux/module.h>
#include <linux/log2.h>
#include <linux/sizes.h>
#include <asm/trace.h>
#include <asm/kvm_ppc.h>
@ -867,6 +868,149 @@ long kvmppc_h_clear_mod(struct kvm_vcpu *vcpu, unsigned long flags,
return ret;
}
static int kvmppc_get_hpa(struct kvm_vcpu *vcpu, unsigned long gpa,
int writing, unsigned long *hpa,
struct kvm_memory_slot **memslot_p)
{
struct kvm *kvm = vcpu->kvm;
struct kvm_memory_slot *memslot;
unsigned long gfn, hva, pa, psize = PAGE_SHIFT;
unsigned int shift;
pte_t *ptep, pte;
/* Find the memslot for this address */
gfn = gpa >> PAGE_SHIFT;
memslot = __gfn_to_memslot(kvm_memslots_raw(kvm), gfn);
if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID))
return H_PARAMETER;
/* Translate to host virtual address */
hva = __gfn_to_hva_memslot(memslot, gfn);
/* Try to find the host pte for that virtual address */
ptep = __find_linux_pte(vcpu->arch.pgdir, hva, NULL, &shift);
if (!ptep)
return H_TOO_HARD;
pte = kvmppc_read_update_linux_pte(ptep, writing);
if (!pte_present(pte))
return H_TOO_HARD;
/* Convert to a physical address */
if (shift)
psize = 1UL << shift;
pa = pte_pfn(pte) << PAGE_SHIFT;
pa |= hva & (psize - 1);
pa |= gpa & ~PAGE_MASK;
if (hpa)
*hpa = pa;
if (memslot_p)
*memslot_p = memslot;
return H_SUCCESS;
}
static long kvmppc_do_h_page_init_zero(struct kvm_vcpu *vcpu,
unsigned long dest)
{
struct kvm_memory_slot *memslot;
struct kvm *kvm = vcpu->kvm;
unsigned long pa, mmu_seq;
long ret = H_SUCCESS;
int i;
/* Used later to detect if we might have been invalidated */
mmu_seq = kvm->mmu_notifier_seq;
smp_rmb();
ret = kvmppc_get_hpa(vcpu, dest, 1, &pa, &memslot);
if (ret != H_SUCCESS)
return ret;
/* Check if we've been invalidated */
raw_spin_lock(&kvm->mmu_lock.rlock);
if (mmu_notifier_retry(kvm, mmu_seq)) {
ret = H_TOO_HARD;
goto out_unlock;
}
/* Zero the page */
for (i = 0; i < SZ_4K; i += L1_CACHE_BYTES, pa += L1_CACHE_BYTES)
dcbz((void *)pa);
kvmppc_update_dirty_map(memslot, dest >> PAGE_SHIFT, PAGE_SIZE);
out_unlock:
raw_spin_unlock(&kvm->mmu_lock.rlock);
return ret;
}
static long kvmppc_do_h_page_init_copy(struct kvm_vcpu *vcpu,
unsigned long dest, unsigned long src)
{
unsigned long dest_pa, src_pa, mmu_seq;
struct kvm_memory_slot *dest_memslot;
struct kvm *kvm = vcpu->kvm;
long ret = H_SUCCESS;
/* Used later to detect if we might have been invalidated */
mmu_seq = kvm->mmu_notifier_seq;
smp_rmb();
ret = kvmppc_get_hpa(vcpu, dest, 1, &dest_pa, &dest_memslot);
if (ret != H_SUCCESS)
return ret;
ret = kvmppc_get_hpa(vcpu, src, 0, &src_pa, NULL);
if (ret != H_SUCCESS)
return ret;
/* Check if we've been invalidated */
raw_spin_lock(&kvm->mmu_lock.rlock);
if (mmu_notifier_retry(kvm, mmu_seq)) {
ret = H_TOO_HARD;
goto out_unlock;
}
/* Copy the page */
memcpy((void *)dest_pa, (void *)src_pa, SZ_4K);
kvmppc_update_dirty_map(dest_memslot, dest >> PAGE_SHIFT, PAGE_SIZE);
out_unlock:
raw_spin_unlock(&kvm->mmu_lock.rlock);
return ret;
}
long kvmppc_rm_h_page_init(struct kvm_vcpu *vcpu, unsigned long flags,
unsigned long dest, unsigned long src)
{
struct kvm *kvm = vcpu->kvm;
u64 pg_mask = SZ_4K - 1; /* 4K page size */
long ret = H_SUCCESS;
/* Don't handle radix mode here, go up to the virtual mode handler */
if (kvm_is_radix(kvm))
return H_TOO_HARD;
/* 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_do_h_page_init_copy(vcpu, dest, src);
else if (flags & H_ZERO_PAGE)
ret = kvmppc_do_h_page_init_zero(vcpu, dest);
/* We can ignore the other flags */
return ret;
}
void kvmppc_invalidate_hpte(struct kvm *kvm, __be64 *hptep,
unsigned long pte_index)
{

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@ -2281,7 +2281,7 @@ hcall_real_table:
#endif
.long 0 /* 0x24 - H_SET_SPRG0 */
.long DOTSYM(kvmppc_h_set_dabr) - hcall_real_table
.long 0 /* 0x2c */
.long DOTSYM(kvmppc_rm_h_page_init) - hcall_real_table
.long 0 /* 0x30 */
.long 0 /* 0x34 */
.long 0 /* 0x38 */