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hw/riscv: virt: Increase maximum number of allowed CPUs 

To facilitate software development of RISC-V systems with large number
of HARTs, we increase the maximum number of allowed CPUs to 512 (2^9).

We also add a detailed source level comments about limit defines which
impact the physical address space utilization.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Frank Chang <frank.chang@sifive.com>
Message-Id: <20220220085526.808674-6-anup@brainfault.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
This commit is contained in:
Anup Patel 2022-02-20 14:25:26 +05:30 committed by Alistair Francis
parent c65bc383ed
commit 0631aaae31
2 changed files with 11 additions and 1 deletions
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10
hw/riscv/virt.c
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@ -45,6 +45,16 @@
#include "hw/pci-host/gpex.h"
#include "hw/display/ramfb.h"
/*
* The virt machine physical address space used by some of the devices
* namely ACLINT, PLIC, APLIC, and IMSIC depend on number of Sockets,
* number of CPUs, and number of IMSIC guest files.
*
* Various limits defined by VIRT_SOCKETS_MAX_BITS, VIRT_CPUS_MAX_BITS,
* and VIRT_IRQCHIP_MAX_GUESTS_BITS are tuned for maximum utilization
* of virt machine physical address space.
*/
#define VIRT_IMSIC_GROUP_MAX_SIZE (1U << IMSIC_MMIO_GROUP_MIN_SHIFT)
#if VIRT_IMSIC_GROUP_MAX_SIZE < \
IMSIC_GROUP_SIZE(VIRT_CPUS_MAX_BITS, VIRT_IRQCHIP_MAX_GUESTS_BITS)

2
include/hw/riscv/virt.h
View File

@ -24,7 +24,7 @@
#include "hw/block/flash.h"
#include "qom/object.h"
#define VIRT_CPUS_MAX_BITS 3
#define VIRT_CPUS_MAX_BITS 9
#define VIRT_CPUS_MAX (1 << VIRT_CPUS_MAX_BITS)
#define VIRT_SOCKETS_MAX_BITS 2
#define VIRT_SOCKETS_MAX (1 << VIRT_SOCKETS_MAX_BITS)