From: Halil Pasic <pasic@linux.ibm.com>
To: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc: linux-s390@vger.kernel.org, Mike Anderson <andmike@linux.ibm.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Robin Murphy <robin.murphy@arm.com>,
x86@kernel.org, Ram Pai <linuxram@us.ibm.com>,
linux-kernel@vger.kernel.org,
Alexey Dobriyan <adobriyan@gmail.com>,
iommu@lists.linux-foundation.org, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>,
linux-fsdevel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
linuxppc-dev@lists.ozlabs.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 3/3] fs/core/vmcore: Move sev_active() reference to x86 arch code
Date: Fri, 12 Jul 2019 15:09:12 +0200 [thread overview]
Message-ID: <20190712150912.3097215e.pasic@linux.ibm.com> (raw)
In-Reply-To: <20190712053631.9814-4-bauerman@linux.ibm.com>
On Fri, 12 Jul 2019 02:36:31 -0300
Thiago Jung Bauermann <bauerman@linux.ibm.com> wrote:
> Secure Encrypted Virtualization is an x86-specific feature, so it shouldn't
> appear in generic kernel code because it forces non-x86 architectures to
> define the sev_active() function, which doesn't make a lot of sense.
sev_active() might be just bad (too specific) name for a general
concept. s390 code defines it drives the right behavior in
kernel/dma/direct.c (which uses it).
>
> To solve this problem, add an x86 elfcorehdr_read() function to override
> the generic weak implementation. To do that, it's necessary to make
> read_from_oldmem() public so that it can be used outside of vmcore.c.
>
> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
> ---
> arch/x86/kernel/crash_dump_64.c | 5 +++++
> fs/proc/vmcore.c | 8 ++++----
> include/linux/crash_dump.h | 14 ++++++++++++++
> include/linux/mem_encrypt.h | 1 -
> 4 files changed, 23 insertions(+), 5 deletions(-)
Does not seem to apply to today's or yesterdays master.
>
> diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c
> index 22369dd5de3b..045e82e8945b 100644
> --- a/arch/x86/kernel/crash_dump_64.c
> +++ b/arch/x86/kernel/crash_dump_64.c
> @@ -70,3 +70,8 @@ ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize,
> {
> return __copy_oldmem_page(pfn, buf, csize, offset, userbuf, true);
> }
> +
> +ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
> +{
> + return read_from_oldmem(buf, count, ppos, 0, sev_active());
> +}
> diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
> index 57957c91c6df..ca1f20bedd8c 100644
> --- a/fs/proc/vmcore.c
> +++ b/fs/proc/vmcore.c
> @@ -100,9 +100,9 @@ static int pfn_is_ram(unsigned long pfn)
> }
>
> /* Reads a page from the oldmem device from given offset. */
> -static ssize_t read_from_oldmem(char *buf, size_t count,
> - u64 *ppos, int userbuf,
> - bool encrypted)
> +ssize_t read_from_oldmem(char *buf, size_t count,
> + u64 *ppos, int userbuf,
> + bool encrypted)
> {
> unsigned long pfn, offset;
> size_t nr_bytes;
> @@ -166,7 +166,7 @@ void __weak elfcorehdr_free(unsigned long long addr)
> */
> ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
> {
> - return read_from_oldmem(buf, count, ppos, 0, sev_active());
> + return read_from_oldmem(buf, count, ppos, 0, false);
> }
>
> /*
> diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h
> index f774c5eb9e3c..4664fc1871de 100644
> --- a/include/linux/crash_dump.h
> +++ b/include/linux/crash_dump.h
> @@ -115,4 +115,18 @@ static inline int vmcore_add_device_dump(struct vmcoredd_data *data)
> return -EOPNOTSUPP;
> }
> #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
> +
> +#ifdef CONFIG_PROC_VMCORE
> +ssize_t read_from_oldmem(char *buf, size_t count,
> + u64 *ppos, int userbuf,
> + bool encrypted);
> +#else
> +static inline ssize_t read_from_oldmem(char *buf, size_t count,
> + u64 *ppos, int userbuf,
> + bool encrypted)
> +{
> + return -EOPNOTSUPP;
> +}
> +#endif /* CONFIG_PROC_VMCORE */
> +
> #endif /* LINUX_CRASHDUMP_H */
> diff --git a/include/linux/mem_encrypt.h b/include/linux/mem_encrypt.h
> index f2e399fb626b..a3747fcae466 100644
> --- a/include/linux/mem_encrypt.h
> +++ b/include/linux/mem_encrypt.h
> @@ -21,7 +21,6 @@
>
> #else /* !CONFIG_ARCH_HAS_MEM_ENCRYPT */
>
> -static inline bool sev_active(void) { return false; }
This is the implementation for the guys that don't
have ARCH_HAS_MEM_ENCRYPT.
Means sev_active() may not be used in such code after this
patch. What about
static inline bool force_dma_unencrypted(void)
{
return sev_active();
}
in kernel/dma/direct.c?
Regards,
Halil
> static inline bool mem_encrypt_active(void) { return false; }
>
> #endif /* CONFIG_ARCH_HAS_MEM_ENCRYPT */
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next prev parent reply other threads:[~2019-07-12 15:17 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-12 5:36 [PATCH 0/3] Remove x86-specific code from generic headers Thiago Jung Bauermann
2019-07-12 5:36 ` [PATCH 1/3] x86/Kconfig: Move ARCH_HAS_MEM_ENCRYPT to arch/Kconfig Thiago Jung Bauermann
2019-07-12 16:04 ` Thomas Gleixner
2019-07-12 23:35 ` Thiago Jung Bauermann
2019-07-12 5:36 ` [PATCH 2/3] DMA mapping: Move SME handling to x86-specific files Thiago Jung Bauermann
2019-07-12 7:13 ` Christoph Hellwig
2019-07-12 23:42 ` Thiago Jung Bauermann
2019-07-12 16:09 ` Thomas Gleixner
2019-07-18 19:47 ` Thiago Jung Bauermann
2019-07-19 9:05 ` kbuild test robot
2019-07-20 0:22 ` Thiago Jung Bauermann
2019-07-12 5:36 ` [PATCH 3/3] fs/core/vmcore: Move sev_active() reference to x86 arch code Thiago Jung Bauermann
2019-07-12 13:09 ` Halil Pasic [this message]
2019-07-12 14:08 ` Christoph Hellwig
2019-07-12 14:51 ` Halil Pasic
2019-07-12 15:11 ` Christoph Hellwig
2019-07-12 15:42 ` Halil Pasic
2019-07-13 8:08 ` Christoph Hellwig
2019-07-12 21:55 ` Thiago Jung Bauermann
2019-07-15 14:03 ` Halil Pasic
2019-07-15 14:30 ` Christoph Hellwig
2019-07-15 15:44 ` Lendacky, Thomas
2019-07-15 20:14 ` Thiago Jung Bauermann
2019-07-13 4:45 [PATCH 0/3] Remove x86-specific code from generic headers Thiago Jung Bauermann
2019-07-13 4:45 ` [PATCH 3/3] fs/core/vmcore: Move sev_active() reference to x86 arch code Thiago Jung Bauermann
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