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    SubjectRe: [PATCH v2 03/13] powerpc/prom_init: Add the ESM call to prom_init
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    On 13/07/2019 16:00, Thiago Jung Bauermann wrote:
    > From: Ram Pai <linuxram@us.ibm.com>
    >
    > Make the Enter-Secure-Mode (ESM) ultravisor call to switch the VM to secure
    > mode. Add "svm=" command line option to turn on switching to secure mode.
    >
    > Signed-off-by: Ram Pai <linuxram@us.ibm.com>
    > [ andmike: Generate an RTAS os-term hcall when the ESM ucall fails. ]
    > Signed-off-by: Michael Anderson <andmike@linux.ibm.com>
    > [ bauerman: Cleaned up the code a bit. ]
    > Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
    > ---
    > .../admin-guide/kernel-parameters.txt | 5 +
    > arch/powerpc/include/asm/ultravisor-api.h | 1 +
    > arch/powerpc/kernel/prom_init.c | 99 +++++++++++++++++++
    > 3 files changed, 105 insertions(+)
    >
    > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
    > index 7b15abf7db21..c611891b5992 100644
    > --- a/Documentation/admin-guide/kernel-parameters.txt
    > +++ b/Documentation/admin-guide/kernel-parameters.txt
    > @@ -4585,6 +4585,11 @@
    > /sys/power/pm_test). Only available when CONFIG_PM_DEBUG
    > is set. Default value is 5.
    >
    > + svm= [PPC]
    > + Format: { on | off | y | n | 1 | 0 }
    > + This parameter controls use of the Protected
    > + Execution Facility on pSeries.
    > +
    > swapaccount=[0|1]
    > [KNL] Enable accounting of swap in memory resource
    > controller if no parameter or 1 is given or disable
    > diff --git a/arch/powerpc/include/asm/ultravisor-api.h b/arch/powerpc/include/asm/ultravisor-api.h
    > index c8180427fa01..fe9a0d8d7673 100644
    > --- a/arch/powerpc/include/asm/ultravisor-api.h
    > +++ b/arch/powerpc/include/asm/ultravisor-api.h
    > @@ -19,6 +19,7 @@
    >
    > /* opcodes */
    > #define UV_WRITE_PATE 0xF104
    > +#define UV_ESM 0xF110
    > #define UV_RETURN 0xF11C
    > #define UV_REGISTER_MEM_SLOT 0xF120
    > #define UV_UNREGISTER_MEM_SLOT 0xF124
    > diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
    > index a3fb90bb5a39..6389a992451b 100644
    > --- a/arch/powerpc/kernel/prom_init.c
    > +++ b/arch/powerpc/kernel/prom_init.c
    > @@ -44,6 +44,7 @@
    > #include <asm/sections.h>
    > #include <asm/machdep.h>
    > #include <asm/asm-prototypes.h>
    > +#include <asm/ultravisor-api.h>
    >
    > #include <linux/linux_logo.h>
    >
    > @@ -175,6 +176,10 @@ static bool __prombss prom_radix_disable;
    > static bool __prombss prom_xive_disable;
    > #endif
    >
    > +#ifdef CONFIG_PPC_SVM
    > +static bool __prombss prom_svm_enable;
    > +#endif
    > +
    > struct platform_support {
    > bool hash_mmu;
    > bool radix_mmu;
    > @@ -816,6 +821,17 @@ static void __init early_cmdline_parse(void)
    > prom_debug("XIVE disabled from cmdline\n");
    > }
    > #endif /* CONFIG_PPC_PSERIES */
    > +
    > +#ifdef CONFIG_PPC_SVM
    > + opt = prom_strstr(prom_cmd_line, "svm=");
    > + if (opt) {
    > + bool val;
    > +
    > + opt += sizeof("svm=") - 1;
    > + if (!prom_strtobool(opt, &val))
    > + prom_svm_enable = val;
    > + }
    > +#endif /* CONFIG_PPC_SVM */
    > }
    >
    > #ifdef CONFIG_PPC_PSERIES
    > @@ -1716,6 +1732,43 @@ static void __init prom_close_stdin(void)
    > }
    > }
    >
    > +#ifdef CONFIG_PPC_SVM
    > +static int prom_rtas_hcall(uint64_t args)
    > +{
    > + register uint64_t arg1 asm("r3") = H_RTAS;
    > + register uint64_t arg2 asm("r4") = args;
    > +
    > + asm volatile("sc 1\n" : "=r" (arg1) :
    > + "r" (arg1),
    > + "r" (arg2) :);
    > + return arg1;
    > +}
    > +
    > +static struct rtas_args __prombss os_term_args;
    > +
    > +static void __init prom_rtas_os_term(char *str)
    > +{
    > + phandle rtas_node;
    > + __be32 val;
    > + u32 token;
    > +
    > + prom_debug("%s: start...\n", __func__);
    > + rtas_node = call_prom("finddevice", 1, 1, ADDR("/rtas"));
    > + prom_debug("rtas_node: %x\n", rtas_node);
    > + if (!PHANDLE_VALID(rtas_node))
    > + return;
    > +
    > + val = 0;
    > + prom_getprop(rtas_node, "ibm,os-term", &val, sizeof(val));
    > + token = be32_to_cpu(val);
    > + prom_debug("ibm,os-term: %x\n", token);
    > + if (token == 0)
    > + prom_panic("Could not get token for ibm,os-term\n");
    > + os_term_args.token = cpu_to_be32(token);
    > + prom_rtas_hcall((uint64_t)&os_term_args);
    > +}
    > +#endif /* CONFIG_PPC_SVM */
    > +
    > /*
    > * Allocate room for and instantiate RTAS
    > */
    > @@ -3172,6 +3225,49 @@ static void unreloc_toc(void)
    > #endif
    > #endif
    >
    > +#ifdef CONFIG_PPC_SVM
    > +/*
    > + * Perform the Enter Secure Mode ultracall.
    > + */
    > +static int enter_secure_mode(unsigned long kbase, unsigned long fdt)
    > +{
    > + register uint64_t func asm("r3") = UV_ESM;
    > + register uint64_t arg1 asm("r4") = (uint64_t)kbase;
    > + register uint64_t arg2 asm("r5") = (uint64_t)fdt;



    What does UV do with kbase and fdt precisely? Few words in the commit
    log will do.


    > +
    > + asm volatile("sc 2\n"
    > + : "=r"(func)
    > + : "0"(func), "r"(arg1), "r"(arg2)
    > + :);
    > +
    > + return (int)func;


    And why "func"? Is it "function"? Weird name. Thanks,


    > +}
    > +
    > +/*
    > + * Call the Ultravisor to transfer us to secure memory if we have an ESM blob.
    > + */
    > +static void setup_secure_guest(unsigned long kbase, unsigned long fdt)
    > +{
    > + int ret;
    > +
    > + if (!prom_svm_enable)
    > + return;
    > +
    > + /* Switch to secure mode. */
    > + prom_printf("Switching to secure mode.\n");
    > +
    > + ret = enter_secure_mode(kbase, fdt);
    > + if (ret != U_SUCCESS) {
    > + prom_printf("Returned %d from switching to secure mode.\n", ret);
    > + prom_rtas_os_term("Switch to secure mode failed.\n");
    > + }
    > +}
    > +#else
    > +static void setup_secure_guest(unsigned long kbase, unsigned long fdt)
    > +{
    > +}
    > +#endif /* CONFIG_PPC_SVM */
    > +
    > /*
    > * We enter here early on, when the Open Firmware prom is still
    > * handling exceptions and the MMU hash table for us.
    > @@ -3370,6 +3466,9 @@ unsigned long __init prom_init(unsigned long r3, unsigned long r4,
    > unreloc_toc();
    > #endif
    >
    > + /* Move to secure memory if we're supposed to be secure guests. */
    > + setup_secure_guest(kbase, hdr);
    > +
    > __start(hdr, kbase, 0, 0, 0, 0, 0);
    >
    > return 0;
    >

    --
    Alexey

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