Commit 6e74b125 authored by Alexander Shishkin's avatar Alexander Shishkin Committed by Ingo Molnar
Browse files

x86/sev: Move sev_setup_arch() to mem_encrypt.c 



Since commit:

  4d96f910 ("x86/sev: Replace occurrences of sev_active() with cc_platform_has()")

... the SWIOTLB bounce buffer size adjustment and restricted virtio memory
setting also inadvertently apply to TDX: the code is using
cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT) as a gatekeeping condition,
which is also true for TDX, and this is also what we want.

To reflect this, move the corresponding code to generic mem_encrypt.c.

No functional changes intended.

Signed-off-by: default avatarAlexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Reviewed-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20231010145220.3960055-2-alexander.shishkin@linux.intel.com
parent c9babd5d

arch/x86/include/asm/mem_encrypt.h

+2 −2
Original line number Diff line number Diff line
@@ -19,8 +19,10 @@ 


#ifdef CONFIG_X86_MEM_ENCRYPT

void __init mem_encrypt_init(void);

void __init mem_encrypt_setup_arch(void);

#else

static inline void mem_encrypt_init(void) { }

static inline void __init mem_encrypt_setup_arch(void) { }

#endif



#ifdef CONFIG_AMD_MEM_ENCRYPT
@@ -43,7 +45,6 @@ void __init sme_map_bootdata(char *real_mode_data); 
void __init sme_unmap_bootdata(char *real_mode_data);



void __init sme_early_init(void);

void __init sev_setup_arch(void);



void __init sme_encrypt_kernel(struct boot_params *bp);

void __init sme_enable(struct boot_params *bp);
@@ -73,7 +74,6 @@ static inline void __init sme_map_bootdata(char *real_mode_data) { } 
static inline void __init sme_unmap_bootdata(char *real_mode_data) { }



static inline void __init sme_early_init(void) { }

static inline void __init sev_setup_arch(void) { }



static inline void __init sme_encrypt_kernel(struct boot_params *bp) { }

static inline void __init sme_enable(struct boot_params *bp) { }

arch/x86/kernel/setup.c

+1 −1
Original line number Diff line number Diff line
@@ -1124,7 +1124,7 @@ void __init setup_arch(char **cmdline_p) 
	 * Needs to run after memblock setup because it needs the physical

	 * memory size.

	 */

	sev_setup_arch();

	mem_encrypt_setup_arch();



	efi_fake_memmap();

	efi_find_mirror();

arch/x86/mm/mem_encrypt.c

+34 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <linux/swiotlb.h>

#include <linux/cc_platform.h>

#include <linux/mem_encrypt.h>

#include <linux/virtio_anchor.h>



/* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */

bool force_dma_unencrypted(struct device *dev)
@@ -86,3 +87,36 @@ void __init mem_encrypt_init(void) 


	print_mem_encrypt_feature_info();

}



void __init mem_encrypt_setup_arch(void)

{

	phys_addr_t total_mem = memblock_phys_mem_size();

	unsigned long size;



	if (!cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))

		return;



	/*

	 * For SEV and TDX, all DMA has to occur via shared/unencrypted pages.

	 * Kernel uses SWIOTLB to make this happen without changing device

	 * drivers. However, depending on the workload being run, the

	 * default 64MB of SWIOTLB may not be enough and SWIOTLB may

	 * run out of buffers for DMA, resulting in I/O errors and/or

	 * performance degradation especially with high I/O workloads.

	 *

	 * Adjust the default size of SWIOTLB using a percentage of guest

	 * memory for SWIOTLB buffers. Also, as the SWIOTLB bounce buffer

	 * memory is allocated from low memory, ensure that the adjusted size

	 * is within the limits of low available memory.

	 *

	 * The percentage of guest memory used here for SWIOTLB buffers

	 * is more of an approximation of the static adjustment which

	 * 64MB for <1G, and ~128M to 256M for 1G-to-4G, i.e., the 6%

	 */

	size = total_mem * 6 / 100;

	size = clamp_val(size, IO_TLB_DEFAULT_SIZE, SZ_1G);

	swiotlb_adjust_size(size);



	/* Set restricted memory access for virtio. */

	virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc);

}

arch/x86/mm/mem_encrypt_amd.c

+0 −35
Original line number Diff line number Diff line
@@ -20,7 +20,6 @@ 
#include <linux/bitops.h>

#include <linux/dma-mapping.h>

#include <linux/virtio_config.h>

#include <linux/virtio_anchor.h>

#include <linux/cc_platform.h>



#include <asm/tlbflush.h>
@@ -215,40 +214,6 @@ void __init sme_map_bootdata(char *real_mode_data) 
	__sme_early_map_unmap_mem(__va(cmdline_paddr), COMMAND_LINE_SIZE, true);

}



void __init sev_setup_arch(void)

{

	phys_addr_t total_mem = memblock_phys_mem_size();

	unsigned long size;



	if (!cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))

		return;



	/*

	 * For SEV, all DMA has to occur via shared/unencrypted pages.

	 * SEV uses SWIOTLB to make this happen without changing device

	 * drivers. However, depending on the workload being run, the

	 * default 64MB of SWIOTLB may not be enough and SWIOTLB may

	 * run out of buffers for DMA, resulting in I/O errors and/or

	 * performance degradation especially with high I/O workloads.

	 *

	 * Adjust the default size of SWIOTLB for SEV guests using

	 * a percentage of guest memory for SWIOTLB buffers.

	 * Also, as the SWIOTLB bounce buffer memory is allocated

	 * from low memory, ensure that the adjusted size is within

	 * the limits of low available memory.

	 *

	 * The percentage of guest memory used here for SWIOTLB buffers

	 * is more of an approximation of the static adjustment which

	 * 64MB for <1G, and ~128M to 256M for 1G-to-4G, i.e., the 6%

	 */

	size = total_mem * 6 / 100;

	size = clamp_val(size, IO_TLB_DEFAULT_SIZE, SZ_1G);

	swiotlb_adjust_size(size);



	/* Set restricted memory access for virtio. */

	virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc);

}



static unsigned long pg_level_to_pfn(int level, pte_t *kpte, pgprot_t *ret_prot)

{

	unsigned long pfn = 0;