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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v5 5/5] xen/arm64: smpboot: Directly switch to the runtime page-tables
> On 23 Feb 2023, at 15:06, Bertrand Marquis <Bertrand.Marquis@xxxxxxx> wrote: > > Hi Julien, > >> On 27 Jan 2023, at 20:55, Julien Grall <julien@xxxxxxx> wrote: >> >> From: Julien Grall <jgrall@xxxxxxxxxx> >> >> Switching TTBR while the MMU is on is not safe. Now that the identity >> mapping will not clash with the rest of the memory layout, we can avoid >> creating temporary page-tables every time a CPU is brought up. >> >> The arm32 code will use a different approach. So this issue is for now >> only resolved on arm64. >> >> Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx> >> Reviewed-by: Luca Fancellu <luca.fancellu@xxxxxxx> >> Tested-by: Luca Fancellu <luca.fancellu@xxxxxxx> > > Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx > <mailto:bertrand.marquis@xxxxxxx>> Sorry for that. Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx> Cheers Bertrand > > Cheers > Bertrand > >> >> --- >> Changes in v5: >> - Add Luca's reviewed-by and tested-by tags. >> >> Changes in v4: >> - Somehow I forgot to send it in v3. So re-include it. >> >> Changes in v2: >> - Remove arm32 code >> --- >> xen/arch/arm/arm32/smpboot.c | 4 ++++ >> xen/arch/arm/arm64/head.S | 29 +++++++++-------------------- >> xen/arch/arm/arm64/smpboot.c | 15 ++++++++++++++- >> xen/arch/arm/include/asm/smp.h | 1 + >> xen/arch/arm/smpboot.c | 1 + >> 5 files changed, 29 insertions(+), 21 deletions(-) >> >> diff --git a/xen/arch/arm/arm32/smpboot.c b/xen/arch/arm/arm32/smpboot.c >> index e7368665d50d..518e9f9c7e70 100644 >> --- a/xen/arch/arm/arm32/smpboot.c >> +++ b/xen/arch/arm/arm32/smpboot.c >> @@ -21,6 +21,10 @@ int arch_cpu_up(int cpu) >> return platform_cpu_up(cpu); >> } >> >> +void arch_cpu_up_finish(void) >> +{ >> +} >> + >> /* >> * Local variables: >> * mode: C >> diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S >> index 5efd442b24af..a61b4d3c2738 100644 >> --- a/xen/arch/arm/arm64/head.S >> +++ b/xen/arch/arm/arm64/head.S >> @@ -308,6 +308,7 @@ real_start_efi: >> bl check_cpu_mode >> bl cpu_init >> bl create_page_tables >> + load_paddr x0, boot_pgtable >> bl enable_mmu >> >> /* We are still in the 1:1 mapping. Jump to the runtime Virtual >> Address. */ >> @@ -365,29 +366,14 @@ GLOBAL(init_secondary) >> #endif >> bl check_cpu_mode >> bl cpu_init >> - bl create_page_tables >> + load_paddr x0, init_ttbr >> + ldr x0, [x0] >> bl enable_mmu >> >> /* We are still in the 1:1 mapping. Jump to the runtime Virtual >> Address. */ >> ldr x0, =secondary_switched >> br x0 >> secondary_switched: >> - /* >> - * Non-boot CPUs need to move on to the proper pagetables, which >> were >> - * setup in init_secondary_pagetables. >> - * >> - * XXX: This is not compliant with the Arm Arm. >> - */ >> - ldr x4, =init_ttbr /* VA of TTBR0_EL2 stashed by CPU 0 */ >> - ldr x4, [x4] /* Actual value */ >> - dsb sy >> - msr TTBR0_EL2, x4 >> - dsb sy >> - isb >> - tlbi alle2 >> - dsb sy /* Ensure completion of TLB flush */ >> - isb >> - >> #ifdef CONFIG_EARLY_PRINTK >> /* Use a virtual address to access the UART. */ >> ldr x23, =EARLY_UART_VIRTUAL_ADDRESS >> @@ -672,9 +658,13 @@ ENDPROC(create_page_tables) >> * mapping. In other word, the caller is responsible to switch to the runtime >> * mapping. >> * >> - * Clobbers x0 - x3 >> + * Inputs: >> + * x0 : Physical address of the page tables. >> + * >> + * Clobbers x0 - x4 >> */ >> enable_mmu: >> + mov x4, x0 >> PRINT("- Turning on paging -\r\n") >> >> /* >> @@ -685,8 +675,7 @@ enable_mmu: >> dsb nsh >> >> /* Write Xen's PT's paddr into TTBR0_EL2 */ >> - load_paddr x0, boot_pgtable >> - msr TTBR0_EL2, x0 >> + msr TTBR0_EL2, x4 >> isb >> >> mrs x0, SCTLR_EL2 >> diff --git a/xen/arch/arm/arm64/smpboot.c b/xen/arch/arm/arm64/smpboot.c >> index 694fbf67e62a..9637f424699e 100644 >> --- a/xen/arch/arm/arm64/smpboot.c >> +++ b/xen/arch/arm/arm64/smpboot.c >> @@ -106,10 +106,23 @@ int __init arch_cpu_init(int cpu, struct >> dt_device_node *dn) >> >> int arch_cpu_up(int cpu) >> { >> + int rc; >> + >> if ( !smp_enable_ops[cpu].prepare_cpu ) >> return -ENODEV; >> >> - return smp_enable_ops[cpu].prepare_cpu(cpu); >> + update_identity_mapping(true); >> + >> + rc = smp_enable_ops[cpu].prepare_cpu(cpu); >> + if ( rc ) >> + update_identity_mapping(false); >> + >> + return rc; >> +} >> + >> +void arch_cpu_up_finish(void) >> +{ >> + update_identity_mapping(false); >> } >> >> /* >> diff --git a/xen/arch/arm/include/asm/smp.h b/xen/arch/arm/include/asm/smp.h >> index 8133d5c29572..a37ca55bff2c 100644 >> --- a/xen/arch/arm/include/asm/smp.h >> +++ b/xen/arch/arm/include/asm/smp.h >> @@ -25,6 +25,7 @@ extern void noreturn stop_cpu(void); >> extern int arch_smp_init(void); >> extern int arch_cpu_init(int cpu, struct dt_device_node *dn); >> extern int arch_cpu_up(int cpu); >> +extern void arch_cpu_up_finish(void); >> >> int cpu_up_send_sgi(int cpu); >> >> diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c >> index 412ae2286906..4a89b3a8345b 100644 >> --- a/xen/arch/arm/smpboot.c >> +++ b/xen/arch/arm/smpboot.c >> @@ -500,6 +500,7 @@ int __cpu_up(unsigned int cpu) >> init_data.cpuid = ~0; >> smp_up_cpu = MPIDR_INVALID; >> clean_dcache(smp_up_cpu); >> + arch_cpu_up_finish(); >> >> if ( !cpu_online(cpu) ) >> { >> -- >> 2.38.1 >> >> > >
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