81df7153f0
commit 8347b99473a313be6549a5b940bc3c56a71be81c upstream. Copy the incoming @data comman to an internal buffer so that callers can put SEV command buffers on the stack without running afoul of CONFIG_VMAP_STACK=y, i.e. without bombing on vmalloc'd pointers. As of today, the largest supported command takes a 68 byte buffer, i.e. pretty much every command can be put on the stack. Because sev_cmd_mutex is held for the entirety of a transaction, only a single bounce buffer is required. Use the internal buffer unconditionally, as the majority of in-kernel users will soon switch to using the stack. At that point, checking virt_addr_valid() becomes (negligible) overhead in most cases, and supporting both paths slightly increases complexity. Since the commands are all quite small, the cost of the copies is insignificant compared to the latency of communicating with the PSP. Allocate a full page for the buffer as opportunistic preparation for SEV-SNP, which requires the command buffer to be in firmware state for commands that trigger memory writes from the PSP firmware. Using a full page now will allow SEV-SNP support to simply transition the page as needed. Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: Borislav Petkov <bp@suse.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210406224952.4177376-5-seanjc@google.com> Reviewed-by: Brijesh Singh <brijesh.singh@amd.com> Acked-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Cc: Ben Hutchings <benh@debian.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
65 lines
1.3 KiB
C
65 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* AMD Platform Security Processor (PSP) interface driver
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*
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* Copyright (C) 2017-2019 Advanced Micro Devices, Inc.
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*
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* Author: Brijesh Singh <brijesh.singh@amd.com>
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*/
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#ifndef __SEV_DEV_H__
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#define __SEV_DEV_H__
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#include <linux/device.h>
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#include <linux/spinlock.h>
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#include <linux/mutex.h>
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#include <linux/list.h>
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#include <linux/wait.h>
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#include <linux/dmapool.h>
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#include <linux/hw_random.h>
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#include <linux/bitops.h>
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#include <linux/interrupt.h>
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#include <linux/irqreturn.h>
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#include <linux/dmaengine.h>
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#include <linux/psp-sev.h>
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#include <linux/miscdevice.h>
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#include <linux/capability.h>
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#define SEV_CMD_COMPLETE BIT(1)
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#define SEV_CMDRESP_CMD_SHIFT 16
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#define SEV_CMDRESP_IOC BIT(0)
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struct sev_misc_dev {
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struct kref refcount;
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struct miscdevice misc;
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};
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struct sev_device {
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struct device *dev;
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struct psp_device *psp;
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void __iomem *io_regs;
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struct sev_vdata *vdata;
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int state;
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unsigned int int_rcvd;
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wait_queue_head_t int_queue;
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struct sev_misc_dev *misc;
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struct sev_data_init init_cmd_buf;
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u8 api_major;
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u8 api_minor;
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u8 build;
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void *cmd_buf;
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};
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int sev_dev_init(struct psp_device *psp);
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void sev_dev_destroy(struct psp_device *psp);
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void sev_pci_init(void);
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void sev_pci_exit(void);
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#endif /* __SEV_DEV_H */
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