a32a8813d0
lguest never checked for pending interrupts when enabling interrupts, and things still worked. However, it makes a significant difference to TCP performance, so it's time we fixed it by introducing a pending_irq flag and checking it on irq_restore and irq_enable. These two routines are now too big to patch into the 8/10 bytes patch space, so we drop that code. Note: The high latency on interrupt delivery had a very curious effect: once everything else was optimized, networking without GSO was faster than networking with GSO, since more interrupts were sent and hence a greater chance of one getting through to the Guest! Note2: (Almost) Closing the same loophole for iret doesn't have any measurable effect, so I'm leaving that patch for the moment. Before: 1GB tcpblast Guest->Host: 30.7 seconds 1GB tcpblast Guest->Host (no GSO): 76.0 seconds After: 1GB tcpblast Guest->Host: 6.8 seconds 1GB tcpblast Guest->Host (no GSO): 27.8 seconds Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
64 lines
2.3 KiB
C
64 lines
2.3 KiB
C
/* Things the lguest guest needs to know. Note: like all lguest interfaces,
|
|
* this is subject to wild and random change between versions. */
|
|
#ifndef _LINUX_LGUEST_H
|
|
#define _LINUX_LGUEST_H
|
|
|
|
#ifndef __ASSEMBLY__
|
|
#include <linux/time.h>
|
|
#include <asm/irq.h>
|
|
#include <asm/lguest_hcall.h>
|
|
|
|
#define LG_CLOCK_MIN_DELTA 100UL
|
|
#define LG_CLOCK_MAX_DELTA ULONG_MAX
|
|
|
|
/*G:032 The second method of communicating with the Host is to via "struct
|
|
* lguest_data". Once the Guest's initialization hypercall tells the Host where
|
|
* this is, the Guest and Host both publish information in it. :*/
|
|
struct lguest_data
|
|
{
|
|
/* 512 == enabled (same as eflags in normal hardware). The Guest
|
|
* changes interrupts so often that a hypercall is too slow. */
|
|
unsigned int irq_enabled;
|
|
/* Fine-grained interrupt disabling by the Guest */
|
|
DECLARE_BITMAP(blocked_interrupts, LGUEST_IRQS);
|
|
|
|
/* The Host writes the virtual address of the last page fault here,
|
|
* which saves the Guest a hypercall. CR2 is the native register where
|
|
* this address would normally be found. */
|
|
unsigned long cr2;
|
|
|
|
/* Wallclock time set by the Host. */
|
|
struct timespec time;
|
|
|
|
/* Interrupt pending set by the Host. The Guest should do a hypercall
|
|
* if it re-enables interrupts and sees this set (to X86_EFLAGS_IF). */
|
|
int irq_pending;
|
|
|
|
/* Async hypercall ring. Instead of directly making hypercalls, we can
|
|
* place them in here for processing the next time the Host wants.
|
|
* This batching can be quite efficient. */
|
|
|
|
/* 0xFF == done (set by Host), 0 == pending (set by Guest). */
|
|
u8 hcall_status[LHCALL_RING_SIZE];
|
|
/* The actual registers for the hypercalls. */
|
|
struct hcall_args hcalls[LHCALL_RING_SIZE];
|
|
|
|
/* Fields initialized by the Host at boot: */
|
|
/* Memory not to try to access */
|
|
unsigned long reserve_mem;
|
|
/* KHz for the TSC clock. */
|
|
u32 tsc_khz;
|
|
/* Page where the top-level pagetable is */
|
|
unsigned long pgdir;
|
|
|
|
/* Fields initialized by the Guest at boot: */
|
|
/* Instruction range to suppress interrupts even if enabled */
|
|
unsigned long noirq_start, noirq_end;
|
|
/* Address above which page tables are all identical. */
|
|
unsigned long kernel_address;
|
|
/* The vector to try to use for system calls (0x40 or 0x80). */
|
|
unsigned int syscall_vec;
|
|
};
|
|
extern struct lguest_data lguest_data;
|
|
#endif /* __ASSEMBLY__ */
|
|
#endif /* _LINUX_LGUEST_H */
|