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ANDROID: KVM: arm64: Parse reserved-memory node for pkvm guest firmware region

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Add support for a "linux,pkvm-guest-firmware-memory" reserved memory
region, which can be used to identify a firmware image for protected
VMs. If pKVM fails to initialise and a firmware region is advertised,
then the memory is cleared during boot.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Will Deacon <willdeacon@google.com>
Bug: 254819795
Change-Id: Ibfcc0ff00d4b8a42747452047856cb9ba8def4c4
This commit is contained in:
Will Deacon
2020-11-17 13:05:03 +00:00
committed by Will Deacon
parent 14e14cc4e9
commit 27b23af252
1 changed files with 61 additions and 0 deletions
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61
arch/arm64/kvm/pkvm.c
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@@ -4,16 +4,21 @@
* Author: Quentin Perret <qperret@google.com>
*/
#include <linux/io.h>
#include <linux/kvm_host.h>
#include <linux/memblock.h>
#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/of_fdt.h>
#include <linux/of_reserved_mem.h>
#include <linux/sort.h>
#include <asm/kvm_pkvm.h>
#include "hyp_constants.h"
static struct reserved_mem *pkvm_firmware_mem;
static struct memblock_region *hyp_memory = kvm_nvhe_sym(hyp_memory);
static unsigned int *hyp_memblock_nr_ptr = &kvm_nvhe_sym(hyp_memblock_nr);
@@ -248,3 +253,59 @@ int pkvm_init_host_vm(struct kvm *host_kvm, unsigned long type)
host_kvm->arch.pkvm.enabled = true;
return 0;
}
static int __init pkvm_firmware_rmem_err(struct reserved_mem *rmem,
const char *reason)
{
phys_addr_t end = rmem->base + rmem->size;
kvm_err("Ignoring pkvm guest firmware memory reservation [%pa - %pa]: %s\n",
&rmem->base, &end, reason);
return -EINVAL;
}
static int __init pkvm_firmware_rmem_init(struct reserved_mem *rmem)
{
unsigned long node = rmem->fdt_node;
if (pkvm_firmware_mem)
return pkvm_firmware_rmem_err(rmem, "duplicate reservation");
if (!of_get_flat_dt_prop(node, "no-map", NULL))
return pkvm_firmware_rmem_err(rmem, "missing \"no-map\" property");
if (of_get_flat_dt_prop(node, "reusable", NULL))
return pkvm_firmware_rmem_err(rmem, "\"reusable\" property unsupported");
if (!PAGE_ALIGNED(rmem->base))
return pkvm_firmware_rmem_err(rmem, "base is not page-aligned");
if (!PAGE_ALIGNED(rmem->size))
return pkvm_firmware_rmem_err(rmem, "size is not page-aligned");
pkvm_firmware_mem = rmem;
return 0;
}
RESERVEDMEM_OF_DECLARE(pkvm_firmware, "linux,pkvm-guest-firmware-memory",
pkvm_firmware_rmem_init);
static int __init pkvm_firmware_rmem_clear(void)
{
void *addr;
phys_addr_t size;
if (likely(!pkvm_firmware_mem) || is_protected_kvm_enabled())
return 0;
kvm_info("Clearing unused pKVM firmware memory\n");
size = pkvm_firmware_mem->size;
addr = memremap(pkvm_firmware_mem->base, size, MEMREMAP_WB);
if (!addr)
return -EINVAL;
memset(addr, 0, size);
dcache_clean_poc((unsigned long)addr, (unsigned long)addr + size);
memunmap(addr);
return 0;
}
device_initcall_sync(pkvm_firmware_rmem_clear);