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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Minios-devel] [UNIKRAFT PATCH v4 2/8] plat: check for and enable extended CPU features
But only do this if code is compiled with SSE/AVX.
Signed-off-by: Florian Schmidt <florian.schmidt@xxxxxxxxx>
Reviewed-by: Yuri Volchkov <yuri.volchkov@xxxxxxxxx>
---
plat/common/include/x86/cpu_defs.h | 22 ++++++++++
plat/kvm/x86/entry64.S | 58 +++++++++++++++++++++----
plat/kvm/x86/setup.c | 15 -------
plat/xen/x86/entry64.S | 68 +++++++++++++++++++++++++++---
plat/xen/x86/setup.c | 15 -------
5 files changed, 135 insertions(+), 43 deletions(-)
diff --git a/plat/common/include/x86/cpu_defs.h
b/plat/common/include/x86/cpu_defs.h
index 9ecec967..e968a832 100644
--- a/plat/common/include/x86/cpu_defs.h
+++ b/plat/common/include/x86/cpu_defs.h
@@ -58,6 +58,7 @@
*/
#define X86_CR0_MP (1 << 1) /* Monitor Coprocessor */
#define X86_CR0_EM (1 << 2) /* Emulation */
+#define X86_CR0_TS (1 << 3) /* Task Switched */
#define X86_CR0_NE (1 << 5) /* Numeric Exception */
#define X86_CR0_PG (1 << 31) /* Paging */
@@ -67,10 +68,31 @@
#define X86_CR4_PAE (1 << 5) /* enable PAE */
#define X86_CR4_OSFXSR (1 << 9) /* OS support for FXSAVE/FXRSTOR */
#define X86_CR4_OSXMMEXCPT (1 << 10) /* OS support for FP exceptions */
+#define X86_CR4_FSGSBASE (1 << 16) /* enable FSGSBASE*/
+#define X86_CR4_OSXSAVE (1 << 18) /* enable XSAVE, extended states */
/*
* Intel CPU features in EFER
*/
#define X86_EFER_LME (1 << 8) /* Long mode enable (R/W) */
+/* CPUID feature bits in ECX and EDX when EAX=1 */
+#define X86_CPUID1_ECX_XSAVE (1 << 26)
+#define X86_CPUID1_ECX_OSXSAVE (1 << 27)
+#define X86_CPUID1_ECX_AVX (1 << 28)
+#define X86_CPUID1_EDX_FPU (1 << 0)
+#define X86_CPUID1_EDX_FXSR (1 << 24)
+#define X86_CPUID1_EDX_SSE (1 << 25)
+/* CPUID feature bits in EBX and ECX when EAX=7, ECX=0 */
+#define X86_CPUID7_EBX_FSGSBASE (1 << 0)
+/* CPUID feature bits when EAX=0xd, ECX=1 */
+#define X86_CPUIDD1_EAX_XSAVEOPT (1<<0)
+
+/*
+ * Extended Control Register 0 (XCR0)
+ */
+#define X86_XCR0_X87 (1 << 0)
+#define X86_XCR0_SSE (1 << 1)
+#define X86_XCR0_AVX (1 << 2)
+
#endif /* __PLAT_CMN_X86_CPU_DEFS_H__ */
diff --git a/plat/kvm/x86/entry64.S b/plat/kvm/x86/entry64.S
index dc3614a2..1ec81364 100644
--- a/plat/kvm/x86/entry64.S
+++ b/plat/kvm/x86/entry64.S
@@ -172,15 +172,57 @@ ENTRY(_libkvmplat_start64)
movq $bootstack, %rsp
xorq %rbp, %rbp
- /* enable FPU and SSE units */
- movq %cr0, %rax
- andq $(~X86_CR0_EM), %rax
- orq $(X86_CR0_MP | X86_CR0_NE), %rax
- movq %rax, %cr0
- movq %cr4, %rax
- orq $(X86_CR4_OSXMMEXCPT | X86_CR4_OSFXSR), %rax
- movq %rax, %cr4
+ /* We will work on cr0 and cr4 multiple times.
+ * We put cr0 into rsi and cr4 into rdi, because cpuid and
+ * xgetbv/xsetbv work on eax/ebx/ecx/edx. */
+ movq %cr0, %rsi
+ movq %cr4, %rdi
+ /* FPU and SSE are part of base x86-64, so no need to check for their
+ * availability before enabling and initializing. */
+ andl $(~(X86_CR0_EM | X86_CR0_TS)), %esi
+ orl $(X86_CR0_MP | X86_CR0_NE), %esi
+ movq %rsi, %cr0
+ fninit
+#if __SSE__
+ orl $(X86_CR4_OSFXSR | X86_CR4_OSXMMEXCPT), %edi
+ movq %rdi, %cr4
ldmxcsr (mxcsr_ptr)
+#endif /* __SSE__ */
+ /* Check capabilities subject to availability as indicated by cpuid.
+ * First, start off with "standard features" */
+ movl $0x1, %eax
+ cpuid
+#if __AVX__
+ /* ecx and edx now contain capability information, so we can now
+ * enable capabilities based on the indicated features */
+ /* OSXSAVE needs to be enabled before AVX */
+ testl $(X86_CPUID1_ECX_XSAVE), %ecx
+ jz noxsave
+ orl $(X86_CR4_OSXSAVE), %edi
+ movq %rdi, %cr4
+ /* now enable AVX. This needs to be last checking cpuid features from
+ * the eax=1 cpuid call, because it clobbers ecx */
+ testl $(X86_CPUID1_ECX_AVX), %ecx
+ jz noavx
+ xorl %ecx, %ecx
+ xgetbv
+ orl $(X86_XCR0_SSE | X86_XCR0_AVX), %eax
+ xsetbv
+noavx:
+noxsave:
+#endif /* __AVX__ */
+ /* Now, check for extended features. */
+ movl $0x7, %eax
+ movl $0x0, %ecx
+ cpuid
+ /* ebx, ecx, edx now contain extended capabilities information. */
+ /* check for and enable FS/GSBASE */
+ testl $(X86_CPUID7_EBX_FSGSBASE), %ebx
+ jz nofsgsbase
+ orl $(X86_CR4_FSGSBASE), %edi
+ movq %rdi, %cr4
+nofsgsbase:
+ /* done setting up CPU capabilities */
/* read multiboot info pointer */
movq -8(%rsp), %rdi
diff --git a/plat/kvm/x86/setup.c b/plat/kvm/x86/setup.c
index e02886d1..47a78dcf 100644
--- a/plat/kvm/x86/setup.c
+++ b/plat/kvm/x86/setup.c
@@ -109,20 +109,6 @@ static inline void _mb_init_mem(struct multiboot_info *mi)
_libkvmplat_stack_top = (void *) (max_addr - __STACK_SIZE);
}
-static inline void _init_cpufeatures(void)
-{
-#if __SSE__
- unsigned long sse_status = 0x1f80;
-#endif
-
- /* FPU */
- asm volatile("fninit");
-
-#if __SSE__
- asm volatile("ldmxcsr %0" : : "m"(sse_status));
-#endif
-}
-
static void _libkvmplat_entry2(void *arg __attribute__((unused)))
{
ukplat_entry_argp(NULL, cmdline, sizeof(cmdline));
@@ -133,7 +119,6 @@ void _libkvmplat_entry(void *arg)
struct multiboot_info *mi = (struct multiboot_info *)arg;
_libkvmplat_init_console();
- _init_cpufeatures();
traps_init();
intctrl_init();
diff --git a/plat/xen/x86/entry64.S b/plat/xen/x86/entry64.S
index c266804a..65401968 100644
--- a/plat/xen/x86/entry64.S
+++ b/plat/xen/x86/entry64.S
@@ -25,6 +25,7 @@
#include <uk/arch/types.h>
#include <uk/arch/limits.h>
+#include <x86/cpu_defs.h>
#include <x86/traps.h>
#include <uk/config.h>
#include <xen/xen.h>
@@ -60,11 +61,68 @@ _libxenplat_start:
#include "entry_hvm.S"
#endif
- cld
- movq stack_start(%rip),%rsp
- andq $(~(__STACK_SIZE-1)), %rsp
- movq %rsi,%rdi
- call _libxenplat_x86entry
+ cld
+ movq stack_start(%rip),%rsp
+ andq $(~(__STACK_SIZE-1)), %rsp
+ movq %rsi, %r8 /* esi contains pointer to start_info page */
+ /* We will work on cr0 and cr4 multiple times.
+ * We put cr0 into rsi and cr4 into rdi, because cpuid and
+ * xgetbv/xsetbv work on eax/ebx/ecx/edx. */
+ movq %cr0, %rsi
+ movq %cr4, %rdi
+ /* FPU and SSE are part of base x86-64, so no need to check for their
+ * availability before enabling and initializing. */
+ andl $(~(X86_CR0_EM | X86_CR0_TS)), %esi
+ orl $(X86_CR0_MP | X86_CR0_NE), %esi
+ movq %rsi, %cr0
+ fninit
+#if __SSE__
+ orl $(X86_CR4_OSFXSR | X86_CR4_OSXMMEXCPT), %edi
+ movq %rdi, %cr4
+ ldmxcsr (mxcsr_ptr)
+#endif /* __SSE__ */
+ /* Check capabilities subject to availability as indicated by cpuid.
+ * First, start off with "standard features" */
+ movl $0x1, %eax
+ cpuid
+#if __AVX__
+ /* ecx and edx now contain capability information, so we can now
+ * enable capabilities based on the indicated features */
+ /* OSXSAVE needs to be enabled before AVX */
+ testl $(X86_CPUID1_ECX_XSAVE), %ecx
+ jz noxsave
+ orl $(X86_CR4_OSXSAVE), %edi
+ movq %rdi, %cr4
+ /* now enable AVX. This needs to be last checking cpuid features from
+ * the eax=1 cpuid call, because it clobbers ecx */
+ testl $(X86_CPUID1_ECX_AVX), %ecx
+ jz noavx
+ xorl %ecx, %ecx
+ xgetbv
+ orl $(X86_XCR0_SSE | X86_XCR0_AVX), %eax
+ xsetbv
+noavx:
+noxsave:
+#endif /* __AVX__ */
+ /* Now, check for extended features. */
+ movl $0x7, %eax
+ movl $0x0, %ecx
+ cpuid
+ /* ebx, ecx, edx now contain extended capabilities information. */
+ /* check for and enable FS/GSBASE */
+ testl $(X86_CPUID7_EBX_FSGSBASE), %ebx
+ jz nofsgsbase
+ orl $(X86_CR4_FSGSBASE), %edi
+ movq %rdi, %cr4
+nofsgsbase:
+ /* Done setting up CPU capabilities, hand over to C entry point. */
+ movq %r8, %rdi /* pass pointer to start_info page to C entry */
+ call _libxenplat_x86entry
+
+.type mxcsr_ptr, @object
+mxcsr_ptr:
+ .long 0x1f80 /* Intel SDM power-on default */
+
stack_start:
.quad _libxenplat_bootstack + (2*__STACK_SIZE)
diff --git a/plat/xen/x86/setup.c b/plat/xen/x86/setup.c
index 35fdd35e..a41d5cb3 100644
--- a/plat/xen/x86/setup.c
+++ b/plat/xen/x86/setup.c
@@ -113,20 +113,6 @@ static inline void _init_traps(void)
traps_init();
}
-static inline void _init_cpufeatures(void)
-{
-#if __SSE__
- unsigned long sse_status = 0x1f80;
-#endif
-
- /* FPU */
- asm volatile("fninit");
-
-#if __SSE__
- asm volatile("ldmxcsr %0" : : "m"(sse_status));
-#endif
-}
-
static inline void _init_shared_info(void)
{
int ret;
@@ -184,7 +170,6 @@ void _libxenplat_x86entry(void *start_info) __noreturn;
void _libxenplat_x86entry(void *start_info)
{
_init_traps();
- _init_cpufeatures();
HYPERVISOR_start_info = (start_info_t *)start_info;
_libxenplat_prepare_console(); /* enables buffering for console */
--
2.20.1
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