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// SPDX-License-Identifier: GPL-2.0-only
/*
* AMD Memory Encryption Support
*
* Copyright (C) 2019 SUSE
*
* Author: Joerg Roedel <jroedel@suse.de>
*/
#define pr_fmt(fmt) "SEV: " fmt
#include <linux/percpu-defs.h>
#include <linux/cc_platform.h>
#include <linux/printk.h>
#include <linux/mm_types.h>
#include <linux/set_memory.h>
#include <linux/memblock.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/cpumask.h>
#include <linux/efi.h>
#include <linux/io.h>
#include <linux/psp-sev.h>
#include <uapi/linux/sev-guest.h>
#include <asm/init.h>
#include <asm/cpu_entry_area.h>
#include <asm/stacktrace.h>
#include <asm/sev.h>
#include <asm/sev-internal.h>
#include <asm/insn-eval.h>
#include <asm/fpu/xcr.h>
#include <asm/processor.h>
#include <asm/realmode.h>
#include <asm/setup.h>
#include <asm/traps.h>
#include <asm/svm.h>
#include <asm/smp.h>
#include <asm/cpu.h>
#include <asm/apic.h>
#include <asm/cpuid/api.h>
#include <asm/cmdline.h>
/* Include code shared with pre-decompression boot stage */
#include "sev-shared.c"
void
early_set_pages_state(unsigned long vaddr, unsigned long paddr,
unsigned long npages, const struct psc_desc *desc)
{
unsigned long paddr_end;
vaddr = vaddr & PAGE_MASK;
paddr = paddr & PAGE_MASK;
paddr_end = paddr + (npages << PAGE_SHIFT);
while (paddr < paddr_end) {
__page_state_change(vaddr, paddr, desc);
vaddr += PAGE_SIZE;
paddr += PAGE_SIZE;
}
}
void __init early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr,
unsigned long npages)
{
struct psc_desc d = {
SNP_PAGE_STATE_PRIVATE,
rip_rel_ptr(&boot_svsm_ca_page),
boot_svsm_caa_pa
};
/*
* This can be invoked in early boot while running identity mapped, so
* use an open coded check for SNP instead of using cc_platform_has().
* This eliminates worries about jump tables or checking boot_cpu_data
* in the cc_platform_has() function.
*/
if (!(sev_status & MSR_AMD64_SEV_SNP_ENABLED))
return;
/*
* Ask the hypervisor to mark the memory pages as private in the RMP
* table.
*/
early_set_pages_state(vaddr, paddr, npages, &d);
}
void __init early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr,
unsigned long npages)
{
struct psc_desc d = {
SNP_PAGE_STATE_SHARED,
rip_rel_ptr(&boot_svsm_ca_page),
boot_svsm_caa_pa
};
/*
* This can be invoked in early boot while running identity mapped, so
* use an open coded check for SNP instead of using cc_platform_has().
* This eliminates worries about jump tables or checking boot_cpu_data
* in the cc_platform_has() function.
*/
if (!(sev_status & MSR_AMD64_SEV_SNP_ENABLED))
return;
/* Ask hypervisor to mark the memory pages shared in the RMP table. */
early_set_pages_state(vaddr, paddr, npages, &d);
}
/*
* Initial set up of SNP relies on information provided by the
* Confidential Computing blob, which can be passed to the kernel
* in the following ways, depending on how it is booted:
*
* - when booted via the boot/decompress kernel:
* - via boot_params
*
* - when booted directly by firmware/bootloader (e.g. CONFIG_PVH):
* - via a setup_data entry, as defined by the Linux Boot Protocol
*
* Scan for the blob in that order.
*/
static struct cc_blob_sev_info *__init find_cc_blob(struct boot_params *bp)
{
struct cc_blob_sev_info *cc_info;
/* Boot kernel would have passed the CC blob via boot_params. */
if (bp->cc_blob_address) {
cc_info = (struct cc_blob_sev_info *)(unsigned long)bp->cc_blob_address;
goto found_cc_info;
}
/*
* If kernel was booted directly, without the use of the
* boot/decompression kernel, the CC blob may have been passed via
* setup_data instead.
*/
cc_info = find_cc_blob_setup_data(bp);
if (!cc_info)
return NULL;
found_cc_info:
if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC)
sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
return cc_info;
}
static void __init svsm_setup(struct cc_blob_sev_info *cc_info)
{
struct snp_secrets_page *secrets = (void *)cc_info->secrets_phys;
struct svsm_call call = {};
u64 pa;
/*
* Record the SVSM Calling Area address (CAA) if the guest is not
* running at VMPL0. The CA will be used to communicate with the
* SVSM to perform the SVSM services.
*/
if (!svsm_setup_ca(cc_info, rip_rel_ptr(&boot_svsm_ca_page)))
return;
/*
* It is very early in the boot and the kernel is running identity
* mapped but without having adjusted the pagetables to where the
* kernel was loaded (physbase), so the get the CA address using
* RIP-relative addressing.
*/
pa = (u64)rip_rel_ptr(&boot_svsm_ca_page);
/*
* Switch over to the boot SVSM CA while the current CA is still 1:1
* mapped and thus addressable with VA == PA. There is no GHCB at this
* point so use the MSR protocol.
*
* SVSM_CORE_REMAP_CA call:
* RAX = 0 (Protocol=0, CallID=0)
* RCX = New CA GPA
*/
call.caa = (struct svsm_ca *)secrets->svsm_caa;
call.rax = SVSM_CORE_CALL(SVSM_CORE_REMAP_CA);
call.rcx = pa;
if (svsm_call_msr_protocol(&call))
sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SVSM_CA_REMAP_FAIL);
boot_svsm_caa_pa = pa;
}
bool __init snp_init(struct boot_params *bp)
{
struct cc_blob_sev_info *cc_info;
if (!bp)
return false;
cc_info = find_cc_blob(bp);
if (!cc_info)
return false;
if (cc_info->secrets_phys && cc_info->secrets_len == PAGE_SIZE)
sev_secrets_pa = cc_info->secrets_phys;
else
return false;
setup_cpuid_table(cc_info);
svsm_setup(cc_info);
/*
* The CC blob will be used later to access the secrets page. Cache
* it here like the boot kernel does.
*/
bp->cc_blob_address = (u32)(unsigned long)cc_info;
return true;
}
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