From: Andrew Cooper Date: Mon, 24 Sep 2018 10:16:21 +0000 (+0100) Subject: AMD/IOMMU: Don't opencode memcpy() in queue_iommu_command() X-Git-Tag: archive/raspbian/4.14.0+80-gd101b417b7-1+rpi1^2~63^2~3184 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=3ccfe3ca9ab89a4f879ac7a51d286bed64dfc83f;p=xen.git AMD/IOMMU: Don't opencode memcpy() in queue_iommu_command() In practice, this allows the compiler to replace the loop with a pair of movs. No functional change. Signed-off-by: Andrew Cooper Reviewed-by: Jan Beulich Reviewed-by: Brian Woods Reviewed-by: Roger Pau Monné --- diff --git a/xen/drivers/passthrough/amd/iommu_cmd.c b/xen/drivers/passthrough/amd/iommu_cmd.c index d4d071e53e..af3a1fb865 100644 --- a/xen/drivers/passthrough/amd/iommu_cmd.c +++ b/xen/drivers/passthrough/amd/iommu_cmd.c @@ -24,8 +24,7 @@ static int queue_iommu_command(struct amd_iommu *iommu, u32 cmd[]) { - u32 tail, head, *cmd_buffer; - int i; + uint32_t tail, head; tail = iommu->cmd_buffer.tail; if ( ++tail == iommu->cmd_buffer.entries ) @@ -35,12 +34,9 @@ static int queue_iommu_command(struct amd_iommu *iommu, u32 cmd[]) IOMMU_CMD_BUFFER_HEAD_OFFSET)); if ( head != tail ) { - cmd_buffer = (u32 *)(iommu->cmd_buffer.buffer + - (iommu->cmd_buffer.tail * - IOMMU_CMD_BUFFER_ENTRY_SIZE)); - - for ( i = 0; i < IOMMU_CMD_BUFFER_U32_PER_ENTRY; i++ ) - cmd_buffer[i] = cmd[i]; + memcpy(iommu->cmd_buffer.buffer + + (iommu->cmd_buffer.tail * IOMMU_CMD_BUFFER_ENTRY_SIZE), + cmd, IOMMU_CMD_BUFFER_ENTRY_SIZE); iommu->cmd_buffer.tail = tail; return 1; diff --git a/xen/include/asm-x86/hvm/svm/amd-iommu-defs.h b/xen/include/asm-x86/hvm/svm/amd-iommu-defs.h index c479f0bb02..1f19cd3d27 100644 --- a/xen/include/asm-x86/hvm/svm/amd-iommu-defs.h +++ b/xen/include/asm-x86/hvm/svm/amd-iommu-defs.h @@ -187,7 +187,6 @@ #define IOMMU_CMD_BUFFER_ENTRY_SIZE 16 #define IOMMU_CMD_BUFFER_POWER_OF2_ENTRIES_PER_PAGE 8 -#define IOMMU_CMD_BUFFER_U32_PER_ENTRY (IOMMU_CMD_BUFFER_ENTRY_SIZE / 4) #define IOMMU_CMD_OPCODE_MASK 0xF0000000 #define IOMMU_CMD_OPCODE_SHIFT 28