Re: [PATCH v5 10/12] hw/mips: malta: Add KVM support

Aurelien Jarno
2014-06-19T16:27:48Z

On Tue, Jun 17, 2014 at 11:10:35PM +0100, James Hogan wrote:
> In KVM mode the bootrom is loaded and executed from the last 1MB of
> DRAM.

What is the reason for that? I am not opposed to that, but if it is
really needed, it means that loading a bootloader into the flash area
(for example YAMON) won't work and that this should be forbidden to the
user.

> Based on "[PATCH 12/12] KVM/MIPS: General KVM support and support for
> SMP Guests" by Sanjay Lal <sanjayl@kymasys.com>.
>
> Signed-off-by: James Hogan <james.hogan@imgtec.com>
> Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
> Cc: Peter Maydell <peter.maydell@linaro.org>
> Cc: Sanjay Lal <sanjayl@kymasys.com>
> ---
> Changes in v5:
> - Kseg0 doesn't actually change size, so use cpu_mips_kseg0_to_phys()
> rather than having the KVM specific cpu_mips_kvm_um_kseg0_to_phys().
>
> Changes in v3:
> - Remove unnecessary includes, especially linux/kvm.h which isn't a
> good idea on non-Linux (Peter Maydell).
>
> Changes in v2:
> - Removal of cps / GIC / SMP support
> - Minimal bootloader modified to execute safely from RAM
> - Remove "Writing bootloader to final 1MB of RAM" printf
> ---
> hw/mips/mips_malta.c | 73 ++++++++++++++++++++++++++++++++++++++--------------
> 1 file changed, 53 insertions(+), 20 deletions(-)
>
> diff --git a/hw/mips/mips_malta.c b/hw/mips/mips_malta.c
> index f4a7d4712952..8bc5392b4223 100644
> --- a/hw/mips/mips_malta.c
> +++ b/hw/mips/mips_malta.c
> @@ -51,6 +51,7 @@
> #include "sysemu/qtest.h"
> #include "qemu/error-report.h"
> #include "hw/empty_slot.h"
> +#include "sysemu/kvm.h"
>
> //#define DEBUG_BOARD_INIT
>
> @@ -603,29 +604,31 @@ static void network_init(PCIBus *pci_bus)
> */
>
> static void write_bootloader (CPUMIPSState *env, uint8_t *base,
> - int64_t kernel_entry)
> + int64_t run_addr, int64_t kernel_entry)
> {
> uint32_t *p;
>
> /* Small bootloader */
> p = (uint32_t *)base;
> - stl_p(p++, 0x0bf00160); /* j 0x1fc00580 */
> +
> + stl_p(p++, 0x08000000 | /* j 0x1fc00580 */
> + ((run_addr + 0x580) & 0x0fffffff) >> 2);
> stl_p(p++, 0x00000000); /* nop */
>
> /* YAMON service vector */
> - stl_p(base + 0x500, 0xbfc00580); /* start: */
> - stl_p(base + 0x504, 0xbfc0083c); /* print_count: */
> - stl_p(base + 0x520, 0xbfc00580); /* start: */
> - stl_p(base + 0x52c, 0xbfc00800); /* flush_cache: */
> - stl_p(base + 0x534, 0xbfc00808); /* print: */
> - stl_p(base + 0x538, 0xbfc00800); /* reg_cpu_isr: */
> - stl_p(base + 0x53c, 0xbfc00800); /* unred_cpu_isr: */
> - stl_p(base + 0x540, 0xbfc00800); /* reg_ic_isr: */
> - stl_p(base + 0x544, 0xbfc00800); /* unred_ic_isr: */
> - stl_p(base + 0x548, 0xbfc00800); /* reg_esr: */
> - stl_p(base + 0x54c, 0xbfc00800); /* unreg_esr: */
> - stl_p(base + 0x550, 0xbfc00800); /* getchar: */
> - stl_p(base + 0x554, 0xbfc00800); /* syscon_read: */
> + stl_p(base + 0x500, run_addr + 0x0580); /* start: */
> + stl_p(base + 0x504, run_addr + 0x083c); /* print_count: */
> + stl_p(base + 0x520, run_addr + 0x0580); /* start: */
> + stl_p(base + 0x52c, run_addr + 0x0800); /* flush_cache: */
> + stl_p(base + 0x534, run_addr + 0x0808); /* print: */
> + stl_p(base + 0x538, run_addr + 0x0800); /* reg_cpu_isr: */
> + stl_p(base + 0x53c, run_addr + 0x0800); /* unred_cpu_isr: */
> + stl_p(base + 0x540, run_addr + 0x0800); /* reg_ic_isr: */
> + stl_p(base + 0x544, run_addr + 0x0800); /* unred_ic_isr: */
> + stl_p(base + 0x548, run_addr + 0x0800); /* reg_esr: */
> + stl_p(base + 0x54c, run_addr + 0x0800); /* unreg_esr: */
> + stl_p(base + 0x550, run_addr + 0x0800); /* getchar: */
> + stl_p(base + 0x554, run_addr + 0x0800); /* syscon_read: */
>
>
> /* Second part of the bootloader */
> @@ -701,7 +704,7 @@ static void write_bootloader (CPUMIPSState *env, uint8_t *base,
> p = (uint32_t *) (base + 0x800);
> stl_p(p++, 0x03e00008); /* jr ra */
> stl_p(p++, 0x24020000); /* li v0,0 */
> - /* 808 YAMON print */
> + /* 808 YAMON print */
> stl_p(p++, 0x03e06821); /* move t5,ra */
> stl_p(p++, 0x00805821); /* move t3,a0 */
> stl_p(p++, 0x00a05021); /* move t2,a1 */
> @@ -774,6 +777,7 @@ static int64_t load_kernel (void)
> uint32_t *prom_buf;
> long prom_size;
> int prom_index = 0;
> + uint64_t (*xlate_to_kseg0) (void *opaque, uint64_t addr);
>
> #ifdef TARGET_WORDS_BIGENDIAN
> big_endian = 1;
> @@ -788,6 +792,11 @@ static int64_t load_kernel (void)
> loaderparams.kernel_filename);
> exit(1);
> }
> + if (kvm_enabled()) {
> + xlate_to_kseg0 = cpu_mips_kvm_um_phys_to_kseg0;
> + } else {
> + xlate_to_kseg0 = cpu_mips_phys_to_kseg0;
> + }
>
> /* load initrd */
> initrd_size = 0;
> @@ -820,7 +829,7 @@ static int64_t load_kernel (void)
> prom_set(prom_buf, prom_index++, "%s", loaderparams.kernel_filename);
> if (initrd_size > 0) {
> prom_set(prom_buf, prom_index++, "rd_start=0x%" PRIx64 " rd_size=%li %s",
> - cpu_mips_phys_to_kseg0(NULL, initrd_offset), initrd_size,
> + xlate_to_kseg0(NULL, initrd_offset), initrd_size,
> loaderparams.kernel_cmdline);
> } else {
> prom_set(prom_buf, prom_index++, "%s", loaderparams.kernel_cmdline);
> @@ -829,6 +838,7 @@ static int64_t load_kernel (void)
> prom_set(prom_buf, prom_index++, "memsize");
> prom_set(prom_buf, prom_index++, "%i",
> MIN(loaderparams.ram_size, 256 << 20));
> +
> prom_set(prom_buf, prom_index++, "modetty0");
> prom_set(prom_buf, prom_index++, "38400n8r");
> prom_set(prom_buf, prom_index++, NULL);
> @@ -863,6 +873,11 @@ static void main_cpu_reset(void *opaque)
> }
>
> malta_mips_config(cpu);
> +
> + if (kvm_enabled()) {
> + /* Start running from the bootloader we wrote to end of RAM */
> + env->active_tc.PC = 0x40000000 + loaderparams.ram_size;
> + }
> }
>
> static void cpu_request_exit(void *opaque, int irq, int level)
> @@ -878,6 +893,7 @@ static
> void mips_malta_init(MachineState *machine)
> {
> ram_addr_t ram_size = machine->ram_size;
> + ram_addr_t ram_low_size;
> const char *cpu_model = machine->cpu_model;
> const char *kernel_filename = machine->kernel_filename;
> const char *kernel_cmdline = machine->kernel_cmdline;
> @@ -892,7 +908,7 @@ void mips_malta_init(MachineState *machine)
> target_long bios_size = FLASH_SIZE;
> const size_t smbus_eeprom_size = 8 * 256;
> uint8_t *smbus_eeprom_buf = g_malloc0(smbus_eeprom_size);
> - int64_t kernel_entry;
> + int64_t kernel_entry, bootloader_run_addr;
> PCIBus *pci_bus;
> ISABus *isa_bus;
> MIPSCPU *cpu;
> @@ -1011,13 +1027,30 @@ void mips_malta_init(MachineState *machine)
> bios = pflash_cfi01_get_memory(fl);
> fl_idx++;
> if (kernel_filename) {
> + ram_low_size = MIN(ram_size, 256 << 20);
> + /* For KVM T&E we reserve 1MB of RAM for running bootloader */
> + if (kvm_enabled()) {
> + ram_low_size -= 0x100000;
> + bootloader_run_addr = 0x40000000 + ram_low_size;
> + } else {
> + bootloader_run_addr = 0xbfc00000;
> + }
> +
> /* Write a small bootloader to the flash location. */
> - loaderparams.ram_size = MIN(ram_size, 256 << 20);
> + loaderparams.ram_size = ram_low_size;
> loaderparams.kernel_filename = kernel_filename;
> loaderparams.kernel_cmdline = kernel_cmdline;
> loaderparams.initrd_filename = initrd_filename;
> kernel_entry = load_kernel();
> - write_bootloader(env, memory_region_get_ram_ptr(bios), kernel_entry);
> +
> + write_bootloader(env, memory_region_get_ram_ptr(bios),
> + bootloader_run_addr, kernel_entry);
> + if (kvm_enabled()) {
> + /* Write the bootloader code @ the end of RAM, 1MB reserved */
> + write_bootloader(env, memory_region_get_ram_ptr(ram_low_preio) +
> + ram_low_size,
> + bootloader_run_addr, kernel_entry);
> + }
> } else {
> /* Load firmware from flash. */
> if (!dinfo) {
> --
> 1.9.3
>
>
>

--
Aurelien Jarno GPG: 4096R/1DDD8C9B
aurelien@aurel32.net http://www.aurel32.net