Re: [PATCH 3/3] KVM: x86: Use FPU API
On Monday 17 May 2010 16:18:22 Avi Kivity wrote: > On 05/17/2010 11:09 AM, Sheng Yang wrote: > > Convert KVM to use generic FPU API. > > > > Signed-off-by: Sheng Yang > > --- > > Like this? (Drop patch 1) > > Will be more readable with a patch that converts host_fx_image to > unlazy_fpu(), and a second patch that converts guest_fx_image to the fpu > API. OK. > I think unlazy_fpu() is even a performance win in case userspace doesn't > do a lot of floating point (which is the case with qemu). I wonder why > we didn't think of it before. ... -- regards Yang, Sheng -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 3/3] KVM: x86: Use FPU API
On 05/17/2010 11:09 AM, Sheng Yang wrote: Convert KVM to use generic FPU API. Signed-off-by: Sheng Yang --- Like this? (Drop patch 1) Will be more readable with a patch that converts host_fx_image to unlazy_fpu(), and a second patch that converts guest_fx_image to the fpu API. I think unlazy_fpu() is even a performance win in case userspace doesn't do a lot of floating point (which is the case with qemu). I wonder why we didn't think of it before. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH 3/3] KVM: x86: Use FPU API
Convert KVM to use generic FPU API.
Signed-off-by: Sheng Yang
---
Like this? (Drop patch 1)
arch/x86/include/asm/kvm_host.h | 18 +-
arch/x86/kvm/x86.c | 70 ++-
2 files changed, 19 insertions(+), 69 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 0c06148..d08bb4a 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -301,8 +301,7 @@ struct kvm_vcpu_arch {
unsigned long mmu_seq;
} update_pte;
- struct i387_fxsave_struct host_fx_image;
- struct i387_fxsave_struct guest_fx_image;
+ struct fpu guest_fpu;
gva_t mmio_fault_cr2;
struct kvm_pio_request pio;
@@ -709,21 +708,6 @@ static inline unsigned long read_msr(unsigned long msr)
}
#endif
-static inline void kvm_fx_save(struct i387_fxsave_struct *image)
-{
- asm("fxsave (%0)":: "r" (image));
-}
-
-static inline void kvm_fx_restore(struct i387_fxsave_struct *image)
-{
- asm("fxrstor (%0)":: "r" (image));
-}
-
-static inline void kvm_fx_finit(void)
-{
- asm("finit");
-}
-
static inline u32 get_rdx_init_val(void)
{
return 0x600; /* P6 family */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7500cba..7be1d36 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -52,6 +52,8 @@
#include
#include
#include
+#include
+#include
#define MAX_IO_MSRS 256
#define CR0_RESERVED_BITS \
@@ -5057,27 +5059,6 @@ out:
}
/*
- * fxsave fpu state. Taken from x86_64/processor.h. To be killed when
- * we have asm/x86/processor.h
- */
-struct fxsave {
- u16 cwd;
- u16 swd;
- u16 twd;
- u16 fop;
- u64 rip;
- u64 rdp;
- u32 mxcsr;
- u32 mxcsr_mask;
- u32 st_space[32]; /* 8*16 bytes for each FP-reg = 128 bytes */
-#ifdef CONFIG_X86_64
- u32 xmm_space[64]; /* 16*16 bytes for each XMM-reg = 256 bytes */
-#else
- u32 xmm_space[32]; /* 8*16 bytes for each XMM-reg = 128 bytes */
-#endif
-};
-
-/*
* Translate a guest virtual address to a guest physical address.
*/
int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
@@ -5100,7 +5081,8 @@ int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
{
- struct fxsave *fxsave = (struct fxsave *)&vcpu->arch.guest_fx_image;
+ struct i387_fxsave_struct *fxsave =
+ &vcpu->arch.guest_fpu.state->fxsave;
memcpy(fpu->fpr, fxsave->st_space, 128);
fpu->fcw = fxsave->cwd;
@@ -5116,7 +5098,8 @@ int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu,
struct kvm_fpu *fpu)
int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
{
- struct fxsave *fxsave = (struct fxsave *)&vcpu->arch.guest_fx_image;
+ struct i387_fxsave_struct *fxsave =
+ &vcpu->arch.guest_fpu.state->fxsave;
memcpy(fxsave->st_space, fpu->fpr, 128);
fxsave->cwd = fpu->fcw;
@@ -5132,41 +5115,26 @@ int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu,
struct kvm_fpu *fpu)
void fx_init(struct kvm_vcpu *vcpu)
{
- unsigned after_mxcsr_mask;
-
- /*
-* Touch the fpu the first time in non atomic context as if
-* this is the first fpu instruction the exception handler
-* will fire before the instruction returns and it'll have to
-* allocate ram with GFP_KERNEL.
-*/
- if (!used_math())
- kvm_fx_save(&vcpu->arch.host_fx_image);
-
- /* Initialize guest FPU by resetting ours and saving into guest's */
- preempt_disable();
- kvm_fx_save(&vcpu->arch.host_fx_image);
- kvm_fx_finit();
- kvm_fx_save(&vcpu->arch.guest_fx_image);
- kvm_fx_restore(&vcpu->arch.host_fx_image);
- preempt_enable();
+ fpu_alloc(&vcpu->arch.guest_fpu);
+ fpu_finit(&vcpu->arch.guest_fpu);
vcpu->arch.cr0 |= X86_CR0_ET;
- after_mxcsr_mask = offsetof(struct i387_fxsave_struct, st_space);
- vcpu->arch.guest_fx_image.mxcsr = 0x1f80;
- memset((void *)&vcpu->arch.guest_fx_image + after_mxcsr_mask,
- 0, sizeof(struct i387_fxsave_struct) - after_mxcsr_mask);
}
EXPORT_SYMBOL_GPL(fx_init);
+static void fx_free(struct kvm_vcpu *vcpu)
+{
+ fpu_free(&vcpu->arch.guest_fpu);
+}
+
void kvm_load_guest_fpu(struct kvm_vcpu *vcpu)
{
if (vcpu->guest_fpu_loaded)
return;
vcpu->guest_fpu_loaded = 1;
- kvm_fx_save(&vcpu->arch.host_fx_image);
- kvm_fx_restore(&vcpu->arch.guest_fx_image);
+ unlazy_fpu(current);
+ fpu_restore_checking(&vcpu->arch.guest_fpu);
trace_kvm_fpu(1);
}
@@ -5176,8 +5144,7 @@ void kvm_put_guest_fpu(struct kvm_vcpu *vcpu)
return;
vcpu->
Re: [PATCH 3/3] KVM: x86: Use FPU API
On 05/14/2010 06:16 AM, Sheng Yang wrote:
Convert KVM to use generic FPU API.
Signed-off-by: Sheng Yang
---
arch/x86/include/asm/kvm_host.h | 18 +-
arch/x86/kvm/x86.c | 73 ---
2 files changed, 23 insertions(+), 68 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index ed48904..beba6f5 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -300,8 +300,7 @@ struct kvm_vcpu_arch {
unsigned long mmu_seq;
} update_pte;
- struct i387_fxsave_struct host_fx_image;
- struct i387_fxsave_struct guest_fx_image;
+ struct fpu host_fpu, guest_fpu;
Do we really need host_fpu? I think we can call unlazy_fpu() instead
and drop host_fpu completely. This might reduce the need for changes in
patch 1 (as well as generally improving the code).
--
Do not meddle in the internals of kernels, for they are subtle and quick to
panic.
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH 3/3] KVM: x86: Use FPU API
Convert KVM to use generic FPU API.
Signed-off-by: Sheng Yang
---
arch/x86/include/asm/kvm_host.h | 18 +-
arch/x86/kvm/x86.c | 73 ---
2 files changed, 23 insertions(+), 68 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index ed48904..beba6f5 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -300,8 +300,7 @@ struct kvm_vcpu_arch {
unsigned long mmu_seq;
} update_pte;
- struct i387_fxsave_struct host_fx_image;
- struct i387_fxsave_struct guest_fx_image;
+ struct fpu host_fpu, guest_fpu;
gva_t mmio_fault_cr2;
struct kvm_pio_request pio;
@@ -709,21 +708,6 @@ static inline unsigned long read_msr(unsigned long msr)
}
#endif
-static inline void kvm_fx_save(struct i387_fxsave_struct *image)
-{
- asm("fxsave (%0)":: "r" (image));
-}
-
-static inline void kvm_fx_restore(struct i387_fxsave_struct *image)
-{
- asm("fxrstor (%0)":: "r" (image));
-}
-
-static inline void kvm_fx_finit(void)
-{
- asm("finit");
-}
-
static inline u32 get_rdx_init_val(void)
{
return 0x600; /* P6 family */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cd8a606..2313f76 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -52,6 +52,8 @@
#include
#include
#include
+#include
+#include
#define MAX_IO_MSRS 256
#define CR0_RESERVED_BITS \
@@ -5069,27 +5071,6 @@ unlock_out:
}
/*
- * fxsave fpu state. Taken from x86_64/processor.h. To be killed when
- * we have asm/x86/processor.h
- */
-struct fxsave {
- u16 cwd;
- u16 swd;
- u16 twd;
- u16 fop;
- u64 rip;
- u64 rdp;
- u32 mxcsr;
- u32 mxcsr_mask;
- u32 st_space[32]; /* 8*16 bytes for each FP-reg = 128 bytes */
-#ifdef CONFIG_X86_64
- u32 xmm_space[64]; /* 16*16 bytes for each XMM-reg = 256 bytes */
-#else
- u32 xmm_space[32]; /* 8*16 bytes for each XMM-reg = 128 bytes */
-#endif
-};
-
-/*
* Translate a guest virtual address to a guest physical address.
*/
int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
@@ -5114,7 +5095,8 @@ int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
{
- struct fxsave *fxsave = (struct fxsave *)&vcpu->arch.guest_fx_image;
+ struct i387_fxsave_struct *fxsave =
+ &vcpu->arch.guest_fpu.state->fxsave;
vcpu_load(vcpu);
@@ -5134,7 +5116,8 @@ int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu,
struct kvm_fpu *fpu)
int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
{
- struct fxsave *fxsave = (struct fxsave *)&vcpu->arch.guest_fx_image;
+ struct i387_fxsave_struct *fxsave =
+ &vcpu->arch.guest_fpu.state->fxsave;
vcpu_load(vcpu);
@@ -5154,41 +5137,30 @@ int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu,
struct kvm_fpu *fpu)
void fx_init(struct kvm_vcpu *vcpu)
{
- unsigned after_mxcsr_mask;
-
- /*
-* Touch the fpu the first time in non atomic context as if
-* this is the first fpu instruction the exception handler
-* will fire before the instruction returns and it'll have to
-* allocate ram with GFP_KERNEL.
-*/
- if (!used_math())
- kvm_fx_save(&vcpu->arch.host_fx_image);
+ fpu_alloc(&vcpu->arch.host_fpu);
+ fpu_alloc(&vcpu->arch.guest_fpu);
- /* Initialize guest FPU by resetting ours and saving into guest's */
- preempt_disable();
- kvm_fx_save(&vcpu->arch.host_fx_image);
- kvm_fx_finit();
- kvm_fx_save(&vcpu->arch.guest_fx_image);
- kvm_fx_restore(&vcpu->arch.host_fx_image);
- preempt_enable();
+ fpu_save(&vcpu->arch.host_fpu);
+ fpu_finit(&vcpu->arch.guest_fpu);
vcpu->arch.cr0 |= X86_CR0_ET;
- after_mxcsr_mask = offsetof(struct i387_fxsave_struct, st_space);
- vcpu->arch.guest_fx_image.mxcsr = 0x1f80;
- memset((void *)&vcpu->arch.guest_fx_image + after_mxcsr_mask,
- 0, sizeof(struct i387_fxsave_struct) - after_mxcsr_mask);
}
EXPORT_SYMBOL_GPL(fx_init);
+static void fx_free(struct kvm_vcpu *vcpu)
+{
+ fpu_free(&vcpu->arch.host_fpu);
+ fpu_free(&vcpu->arch.guest_fpu);
+}
+
void kvm_load_guest_fpu(struct kvm_vcpu *vcpu)
{
if (vcpu->guest_fpu_loaded)
return;
vcpu->guest_fpu_loaded = 1;
- kvm_fx_save(&vcpu->arch.host_fx_image);
- kvm_fx_restore(&vcpu->arch.guest_fx_image);
+ fpu_save(&vcpu->arch.host_fpu);
+ fpu_restore_checking(&vcpu->arch.guest_fpu);
trace_kvm_fpu(1);
}
@@ -5198,8 +5170,8 @@ void kvm_put_guest_fpu(struct kvm_vcpu *vcpu)
return;
