[RFC PATCH] KVM: PPC: BOOK3S: HV: THP support for guest

Aneesh Kumar K.V
2014-05-04T17:30:16Z

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/kvm_book3s_64.h | 146 ++++++++++++++++++++++++++-----
arch/powerpc/kvm/book3s_hv.c | 7 ++
2 files changed, 130 insertions(+), 23 deletions(-)

diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h
index 51388befeddb..f03ea8f90576 100644
--- a/arch/powerpc/include/asm/kvm_book3s_64.h
+++ b/arch/powerpc/include/asm/kvm_book3s_64.h
@@ -77,34 +77,122 @@ static inline long try_lock_hpte(unsigned long *hpte, unsigned long bits)
return old == 0;
}

+static inline int __hpte_actual_psize(unsigned int lp, int psize)
+{
+ int i, shift;
+ unsigned int mask;
+
+ /* start from 1 ignoring MMU_PAGE_4K */
+ for (i = 1; i < MMU_PAGE_COUNT; i++) {
+
+ /* invalid penc */
+ if (mmu_psize_defs[psize].penc[i] == -1)
+ continue;
+ /*
+ * encoding bits per actual page size
+ * PTE LP actual page size
+ * rrrr rrrz >=8KB
+ * rrrr rrzz >=16KB
+ * rrrr rzzz >=32KB
+ * rrrr zzzz >=64KB
+ * .......
+ */
+ shift = mmu_psize_defs[i].shift - LP_SHIFT;
+ if (shift > LP_BITS)
+ shift = LP_BITS;
+ mask = (1 << shift) - 1;
+ if ((lp & mask) == mmu_psize_defs[psize].penc[i])
+ return i;
+ }
+ return -1;
+}
+
static inline unsigned long compute_tlbie_rb(unsigned long v, unsigned long r,
unsigned long pte_index)
{
- unsigned long rb, va_low;
+ int b_size, a_size;
+ unsigned int penc;
+ unsigned long rb = 0, va_low, sllp;
+ unsigned int lp = (r >> LP_SHIFT) & ((1 << LP_BITS) - 1);
+
+ if (!(v & HPTE_V_LARGE)) {
+ /* both base and actual psize is 4k */
+ b_size = MMU_PAGE_4K;
+ a_size = MMU_PAGE_4K;
+ } else {
+ for (b_size = 0; b_size < MMU_PAGE_COUNT; b_size++) {
+
+ /* valid entries have a shift value */
+ if (!mmu_psize_defs[b_size].shift)
+ continue;

+ a_size = __hpte_actual_psize(lp, b_size);
+ if (a_size != -1)
+ break;
+ }
+ }
+ /*
+ * Ignore the top 14 bits of va
+ * v have top two bits covering segment size, hence move
+ * by 16 bits, Also clear the lower HPTE_V_AVPN_SHIFT (7) bits.
+ * AVA field in v also have the lower 23 bits ignored.
+ * For base page size 4K we need 14 .. 65 bits (so need to
+ * collect extra 11 bits)
+ * For others we need 14..14+i
+ */
+ /* This covers 14..54 bits of va*/
rb = (v & ~0x7fUL) << 16; /* AVA field */
+ /*
+ * AVA in v had cleared lower 23 bits. We need to derive
+ * that from pteg index
+ */
va_low = pte_index >> 3;
if (v & HPTE_V_SECONDARY)
va_low = ~va_low;
- /* xor vsid from AVA */
+ /*
+ * get the vpn bits from va_low using reverse of hashing.
+ * In v we have va with 23 bits dropped and then left shifted
+ * HPTE_V_AVPN_SHIFT (7) bits. Now to find vsid we need
+ * right shift it with (SID_SHIFT - (23 - 7))
+ */
if (!(v & HPTE_V_1TB_SEG))
- va_low ^= v >> 12;
+ va_low ^= v >> (SID_SHIFT - 16);
else
- va_low ^= v >> 24;
+ va_low ^= v >> (SID_SHIFT_1T - 16);
va_low &= 0x7ff;
- if (v & HPTE_V_LARGE) {
- rb |= 1; /* L field */
- if (cpu_has_feature(CPU_FTR_ARCH_206) &&
- (r & 0xff000)) {
- /* non-16MB large page, must be 64k */
- /* (masks depend on page size) */
- rb |= 0x1000; /* page encoding in LP field */
- rb |= (va_low & 0x7f) << 16; /* 7b of VA in AVA/LP field */
- rb |= ((va_low << 4) & 0xf0); /* AVAL field (P7 doesn't seem to care) */
- }
- } else {
- /* 4kB page */
- rb |= (va_low & 0x7ff) << 12; /* remaining 11b of VA */
+
+ switch (b_size) {
+ case MMU_PAGE_4K:
+ sllp = ((mmu_psize_defs[a_size].sllp & SLB_VSID_L) >> 6) |
+ ((mmu_psize_defs[a_size].sllp & SLB_VSID_LP) >> 4);
+ rb |= sllp << 5; /* AP field */
+ rb |= (va_low & 0x7ff) << 12; /* remaining 11 bits of AVA */
+ break;
+ default:
+ {
+ int aval_shift;
+ /*
+ * remaining 7bits of AVA/LP fields
+ * Also contain the rr bits of LP
+ */
+ rb |= (va_low & 0x7f) << 16;
+ /*
+ * Now clear not needed LP bits based on actual psize
+ */
+ rb &= ~((1ul << mmu_psize_defs[a_size].shift) - 1);
+ /*
+ * AVAL field 58..77 - base_page_shift bits of va
+ * we have space for 58..64 bits, Missing bits should
+ * be zero filled. +1 is to take care of L bit shift
+ */
+ aval_shift = 64 - (77 - mmu_psize_defs[b_size].shift) + 1;
+ rb |= ((va_low << aval_shift) & 0xfe);
+
+ rb |= 1; /* L field */
+ penc = mmu_psize_defs[b_size].penc[a_size];
+ rb |= penc << 12; /* LP field */
+ break;
+ }
}
rb |= (v >> 54) & 0x300; /* B field */
return rb;
@@ -112,14 +200,26 @@ static inline unsigned long compute_tlbie_rb(unsigned long v, unsigned long r,

static inline unsigned long hpte_page_size(unsigned long h, unsigned long l)
{
+ int size, a_size;
+ /* Look at the 8 bit LP value */
+ unsigned int lp = (l >> LP_SHIFT) & ((1 << LP_BITS) - 1);
+
/* only handle 4k, 64k and 16M pages for now */
if (!(h & HPTE_V_LARGE))
- return 1ul << 12; /* 4k page */
- if ((l & 0xf000) == 0x1000 && cpu_has_feature(CPU_FTR_ARCH_206))
- return 1ul << 16; /* 64k page */
- if ((l & 0xff000) == 0)
- return 1ul << 24; /* 16M page */
- return 0; /* error */
+ return 1ul << 12;
+ else {
+ for (size = 0; size < MMU_PAGE_COUNT; size++) {
+ /* valid entries have a shift value */
+ if (!mmu_psize_defs[size].shift)
+ continue;
+
+ a_size = __hpte_actual_psize(lp, size);
+ if (a_size != -1)
+ return 1ul << mmu_psize_defs[a_size].shift;
+ }
+
+ }
+ return 0;
}

static inline unsigned long hpte_rpn(unsigned long ptel, unsigned long psize)
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 8227dba5af0f..a38d3289320a 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -1949,6 +1949,13 @@ static void kvmppc_add_seg_page_size(struct kvm_ppc_one_seg_page_size **sps,
* support pte_enc here
*/
(*sps)->enc[0].pte_enc = def->penc[linux_psize];
+ /*
+ * Add 16MB MPSS support
+ */
+ if (linux_psize != MMU_PAGE_16M) {
+ (*sps)->enc[1].page_shift = 24;
+ (*sps)->enc[1].pte_enc = def->penc[MMU_PAGE_16M];
+ }
(*sps)++;
}

--
1.9.1