qemu/include/hw/ppc/spapr_ovec.h
David Gibson 2772cf6be9 pseries: Use smaller default hash page tables when guest can resize
We've now implemented a PAPR extension allowing PAPR guest to resize
their hash page table (HPT) during runtime.

This patch makes use of that facility to allocate smaller HPTs by default.
Specifically when a guest is aware of the HPT resize facility, qemu sizes
the HPT to the initial memory size, rather than the maximum memory size on
the assumption that the guest will resize its HPT if necessary for hot
plugged memory.

When the initial memory size is much smaller than the maximum memory size
(a common configuration with e.g. oVirt / RHEV) then this can save
significant memory on the HPT.

If the guest does *not* advertise HPT resize awareness when it makes the
ibm,client-architecture-support call, qemu resizes the HPT for maxmimum
memory size (unless it's been configured not to allow such guests at all).

For now we make that reallocation assuming the guest has not yet used the
HPT at all.  That's true in practice, but not, strictly, an architectural
or PAPR requirement.  If we need to in future we can fix this by having
the client-architecture-support call reboot the guest with the revised
HPT size (the client-architecture-support call is explicitly permitted to
trigger a reboot in this way).

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
2017-07-17 15:07:05 +10:00

82 lines
3.1 KiB
C

/*
* QEMU SPAPR Option/Architecture Vector Definitions
*
* Each architecture option is organized/documented by the following
* in LoPAPR 1.1, Table 244:
*
* <vector number>: the bit-vector in which the option is located
* <vector byte>: the byte offset of the vector entry
* <vector bit>: the bit offset within the vector entry
*
* where each vector entry can be one or more bytes.
*
* Firmware expects a somewhat literal encoding of this bit-vector
* structure, where each entry is stored in little-endian so that the
* byte ordering reflects that of the documentation, but where each bit
* offset is from "left-to-right" in the traditional representation of
* a byte value where the MSB is the left-most bit. Thus, each
* individual byte encodes the option bits in reverse order of the
* documented bit.
*
* These definitions/helpers attempt to abstract away this internal
* representation so that we can define/set/test for individual option
* bits using only the documented values. This is done mainly by relying
* on a bitmap to approximate the documented "bit-vector" structure and
* handling conversations to-from the internal representation under the
* covers.
*
* Copyright IBM Corp. 2016
*
* Authors:
* Michael Roth <mdroth@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#ifndef _SPAPR_OVEC_H
#define _SPAPR_OVEC_H
#include "cpu.h"
#include "migration/vmstate.h"
typedef struct sPAPROptionVector sPAPROptionVector;
#define OV_BIT(byte, bit) ((byte - 1) * BITS_PER_BYTE + bit)
/* option vector 1 */
#define OV1_PPC_3_00 OV_BIT(3, 0) /* guest supports PowerPC 3.00? */
/* option vector 5 */
#define OV5_DRCONF_MEMORY OV_BIT(2, 2)
#define OV5_FORM1_AFFINITY OV_BIT(5, 0)
#define OV5_HP_EVT OV_BIT(6, 5)
#define OV5_HPT_RESIZE OV_BIT(6, 7)
#define OV5_XIVE_EXPLOIT OV_BIT(23, 7)
/* ISA 3.00 MMU features: */
#define OV5_MMU_BOTH OV_BIT(24, 0) /* Radix and hash */
#define OV5_MMU_RADIX_300 OV_BIT(24, 1) /* 1=Radix only, 0=Hash only */
#define OV5_MMU_RADIX_GTSE OV_BIT(26, 1) /* Radix GTSE */
/* interfaces */
sPAPROptionVector *spapr_ovec_new(void);
sPAPROptionVector *spapr_ovec_clone(sPAPROptionVector *ov_orig);
void spapr_ovec_intersect(sPAPROptionVector *ov,
sPAPROptionVector *ov1,
sPAPROptionVector *ov2);
bool spapr_ovec_diff(sPAPROptionVector *ov,
sPAPROptionVector *ov_old,
sPAPROptionVector *ov_new);
void spapr_ovec_cleanup(sPAPROptionVector *ov);
void spapr_ovec_set(sPAPROptionVector *ov, long bitnr);
void spapr_ovec_clear(sPAPROptionVector *ov, long bitnr);
bool spapr_ovec_test(sPAPROptionVector *ov, long bitnr);
sPAPROptionVector *spapr_ovec_parse_vector(target_ulong table_addr, int vector);
int spapr_ovec_populate_dt(void *fdt, int fdt_offset,
sPAPROptionVector *ov, const char *name);
/* migration */
extern const VMStateDescription vmstate_spapr_ovec;
#endif /* !defined (_SPAPR_OVEC_H) */