From: Andy Lutomirski <luto@kernel.org>
To: X86 ML <x86@kernel.org>
Cc: KVM list <kvm@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org, xen-devel <Xen-devel@lists.xen.org>,
Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Arjan van de Ven <arjan@linux.intel.com>
Subject: [PATCH v5 7/9] x86/paravirt: Add paravirt_{read, write}_msr
Date: Sat, 2 Apr 2016 07:01:38 -0700 [thread overview]
Message-ID: <880eebc5dcd2ad9f310d41345f82061ea500e9fa.1459605520.git.luto__7528.09220362014$1459605812$gmane$org@kernel.org> (raw)
In-Reply-To: <cover.1459605520.git.luto@kernel.org>
In-Reply-To: <cover.1459605520.git.luto@kernel.org>
This adds paravirt hooks for unsafe MSR access. On native, they
call native_{read,write}_msr. On Xen, they use
xen_{read,write}_msr_safe.
Nothing uses them yet for ease of bisection. The next patch will
use them in rdmsrl, wrmsrl, etc.
I intentionally didn't make them warn on #GP on Xen. I think that
should be done separately by the Xen maintainers.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/include/asm/msr.h | 5 +++--
arch/x86/include/asm/paravirt.h | 11 +++++++++++
arch/x86/include/asm/paravirt_types.h | 10 ++++++++--
arch/x86/kernel/paravirt.c | 2 ++
arch/x86/xen/enlighten.c | 23 +++++++++++++++++++++++
5 files changed, 47 insertions(+), 4 deletions(-)
diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index 1487054a1a70..13da359881d7 100644
--- a/arch/x86/include/asm/msr.h
+++ b/arch/x86/include/asm/msr.h
@@ -119,8 +119,9 @@ static inline unsigned long long native_read_msr_safe(unsigned int msr,
return EAX_EDX_VAL(val, low, high);
}
-static inline void native_write_msr(unsigned int msr,
- unsigned low, unsigned high)
+/* Can be uninlined because referenced by paravirt */
+notrace static inline void native_write_msr(unsigned int msr,
+ unsigned low, unsigned high)
{
asm volatile("1: wrmsr\n"
"2:\n"
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 2e49228ed9a3..68297d87e85c 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -129,6 +129,17 @@ static inline void wbinvd(void)
#define get_kernel_rpl() (pv_info.kernel_rpl)
+static inline u64 paravirt_read_msr(unsigned msr)
+{
+ return PVOP_CALL1(u64, pv_cpu_ops.read_msr, msr);
+}
+
+static inline void paravirt_write_msr(unsigned msr,
+ unsigned low, unsigned high)
+{
+ return PVOP_VCALL3(pv_cpu_ops.write_msr, msr, low, high);
+}
+
static inline u64 paravirt_read_msr_safe(unsigned msr, int *err)
{
return PVOP_CALL2(u64, pv_cpu_ops.read_msr_safe, msr, err);
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 5a06cccd36f0..b85aec45a1b8 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -155,8 +155,14 @@ struct pv_cpu_ops {
void (*cpuid)(unsigned int *eax, unsigned int *ebx,
unsigned int *ecx, unsigned int *edx);
- /* MSR operations.
- err = 0/-EIO. wrmsr returns 0/-EIO. */
+ /* Unsafe MSR operations. These will warn or panic on failure. */
+ u64 (*read_msr)(unsigned int msr);
+ void (*write_msr)(unsigned int msr, unsigned low, unsigned high);
+
+ /*
+ * Safe MSR operations.
+ * read sets err to 0 or -EIO. write returns 0 or -EIO.
+ */
u64 (*read_msr_safe)(unsigned int msr, int *err);
int (*write_msr_safe)(unsigned int msr, unsigned low, unsigned high);
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 8aad95478ae5..f9583917c7c4 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -339,6 +339,8 @@ __visible struct pv_cpu_ops pv_cpu_ops = {
.write_cr8 = native_write_cr8,
#endif
.wbinvd = native_wbinvd,
+ .read_msr = native_read_msr,
+ .write_msr = native_write_msr,
.read_msr_safe = native_read_msr_safe,
.write_msr_safe = native_write_msr_safe,
.read_pmc = native_read_pmc,
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index ff2df20d0067..548cd3e02b9e 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1092,6 +1092,26 @@ static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
return ret;
}
+static u64 xen_read_msr(unsigned int msr)
+{
+ /*
+ * This will silently swallow a #GP from RDMSR. It may be worth
+ * changing that.
+ */
+ int err;
+
+ return xen_read_msr_safe(msr, &err);
+}
+
+static void xen_write_msr(unsigned int msr, unsigned low, unsigned high)
+{
+ /*
+ * This will silently swallow a #GP from WRMSR. It may be worth
+ * changing that.
+ */
+ xen_write_msr_safe(msr, low, high);
+}
+
void xen_setup_shared_info(void)
{
if (!xen_feature(XENFEAT_auto_translated_physmap)) {
@@ -1222,6 +1242,9 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = {
.wbinvd = native_wbinvd,
+ .read_msr = xen_read_msr,
+ .write_msr = xen_write_msr,
+
.read_msr_safe = xen_read_msr_safe,
.write_msr_safe = xen_write_msr_safe,
--
2.5.5
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next prev parent reply other threads:[~2016-04-02 14:01 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1459605520.git.luto@kernel.org>
2016-04-02 14:01 ` [PATCH v5 1/9] x86/head: Pass a real pt_regs and trapnr to early_fixup_exception Andy Lutomirski
2016-04-13 11:43 ` [tip:x86/asm] x86/head: Pass a real pt_regs and trapnr to early_fixup_exception() tip-bot for Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 2/9] x86/head: Move the early NMI fixup into C Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 3/9] x86/head: Move early exception panic code into early_fixup_exception Andy Lutomirski
2016-04-02 18:39 ` Borislav Petkov
[not found] ` <20160402183919.GA2538@pd.tnic>
2016-04-02 20:13 ` Andy Lutomirski
[not found] ` <CALCETrUJVDpzNQMsY=_jWNOMer+TdW2p4wES4OBCfYU7gq3fbg@mail.gmail.com>
2016-04-02 20:47 ` Borislav Petkov
[not found] ` <20160402204752.GC2538@pd.tnic>
2016-04-02 20:58 ` Andy Lutomirski
[not found] ` <CALCETrXHR3T3PJwOWRFHTMK5WjhDyTJfaJtkiHd+g7evnqp54A@mail.gmail.com>
2016-04-04 11:52 ` Jan Kara
[not found] ` <20160404115206.GG8372@quack.suse.cz>
2016-04-04 12:46 ` Peter Zijlstra
2016-04-04 15:32 ` Andy Lutomirski
[not found] ` <CALCETrVriftUPNZ8pCQ1x9TWDHnRx8fWUvJgCQToPEOxqMLb3w@mail.gmail.com>
2016-04-04 15:36 ` Arjan van de Ven
2016-04-04 16:00 ` Peter Zijlstra
[not found] ` <20160404160042.GB3448@twins.programming.kicks-ass.net>
2016-04-04 19:38 ` Borislav Petkov
[not found] ` <20160404193803.GK351@pd.tnic>
2016-04-04 21:31 ` Andy Lutomirski
[not found] ` <CALCETrVvFTrK1pVmjnfWwwq+5P6+1ghMjh4Wwqm05d=00ejYSw@mail.gmail.com>
2016-04-04 21:40 ` Borislav Petkov
2016-04-13 11:44 ` [tip:x86/asm] x86/head: Move early exception panic code into early_fixup_exception() tip-bot for Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 4/9] x86/traps: Enable all exception handler callbacks early Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 5/9] x86/paravirt: Add _safe to the read_msr and write_msr PV hooks Andy Lutomirski
2016-04-03 8:41 ` Borislav Petkov
[not found] ` <20160403084129.GB19007@pd.tnic>
2016-04-03 13:23 ` Andy Lutomirski
[not found] ` <CALCETrUcqTx00pKYEt49QSKKBKVEx-Uv0D6dzE1-Em6Q-wkSpQ@mail.gmail.com>
2016-04-03 14:07 ` Borislav Petkov
2016-04-13 11:44 ` [tip:x86/asm] x86/paravirt: Add _safe to the read_ms()r and write_msr() PV callbacks tip-bot for Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 6/9] x86/msr: Carry on after a non-"safe" MSR access fails Andy Lutomirski
2016-04-02 14:01 ` Andy Lutomirski [this message]
2016-04-02 14:01 ` [PATCH v5 8/9] x86/paravirt: Make "unsafe" MSR accesses unsafe even if PARAVIRT=y Andy Lutomirski
2016-04-13 11:46 ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 9/9] x86/msr: Set the return value to zero when native_rdmsr_safe fails Andy Lutomirski
2016-04-02 14:24 ` [PATCH v5 0/9] Improve non-"safe" MSR access failure handling Linus Torvalds
[not found] ` <CA+55aFwi2E0A9e7krCG9dkTq7vMZnxsBwtF6_hw6QO0EVObf=g@mail.gmail.com>
2016-04-02 15:13 ` Andy Lutomirski
[not found] ` <CALCETrWP33SR5TCA-baZi8xBrHpWe=wzkuvUM=y4x_MPt1XgYg@mail.gmail.com>
2016-04-02 15:21 ` Linus Torvalds
2016-04-04 16:23 ` Borislav Petkov
[not found] ` <880eebc5dcd2ad9f310d41345f82061ea500e9fa.1459605520.git.luto@kernel.org>
2016-04-04 16:33 ` [PATCH v5 7/9] x86/paravirt: Add paravirt_{read, write}_msr David Vrabel
[not found] ` <5702974A.1030003@citrix.com>
2016-04-04 16:40 ` Andy Lutomirski
2016-04-13 11:45 ` [tip:x86/asm] x86/paravirt: Add paravirt_{read, write}_msr() tip-bot for Andy Lutomirski
2016-04-05 15:38 ` [PATCH v5 0/9] Improve non-"safe" MSR access failure handling Boris Ostrovsky
[not found] ` <20fc047d926150cb08cb9b9f2923519b07ec1a15.1459605520.git.luto@kernel.org>
2016-04-02 18:52 ` [PATCH v5 4/9] x86/traps: Enable all exception handler callbacks early Borislav Petkov
[not found] ` <20160402185227.GB2538@pd.tnic>
2016-04-02 20:16 ` Andy Lutomirski
[not found] ` <CALCETrV7PxgmhU_yXjJSugY88T8Do=vBDuG54fOFSyLp7nGcJA@mail.gmail.com>
2016-04-02 20:52 ` Borislav Petkov
[not found] ` <20160402205248.GD2538@pd.tnic>
2016-04-03 8:07 ` Borislav Petkov
[not found] ` <20160403080737.GA19007@pd.tnic>
2016-04-03 13:22 ` Andy Lutomirski
2016-04-03 13:51 ` Linus Torvalds
[not found] ` <CA+55aFw19X7PO2xd1PpUav1rSyCqUqWgi9+SA7TgjaWMaxexHQ@mail.gmail.com>
2016-04-03 13:55 ` Andy Lutomirski
[not found] ` <CALCETrX_x+tV4m3SwgCfXg9y5gia8eMhhTdUnHuXpXhnULkHRw@mail.gmail.com>
2016-04-03 14:10 ` Borislav Petkov
2016-04-03 14:17 ` Linus Torvalds
[not found] ` <20160403141041.GE19007@pd.tnic>
2016-04-04 15:47 ` Andy Lutomirski
2016-04-13 11:44 ` [tip:x86/asm] " tip-bot for Andy Lutomirski
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